gh-86986: Drop compatibility support for Sphinx 2 (GH-93737)

* Revert "bpo-42843: Keep Sphinx 1.8 and Sphinx 2 compatibility (GH-24282)"

This reverts commit 5c1f15b4b1024cbf0acc85832f0c623d1a4605fd

* Revert "bpo-42579: Make workaround for various versions of Sphinx more robust (GH-23662)"

This reverts commit b63a620014b67a6e63d10783149c41baaf59def8.
(cherry picked from commit 0efe3a1636c143fe0694a8e4d25d6eae19e0d618)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

11 files changed, 18 insertions, 52 deletions

diff --git a/Doc/conf.py b/Doc/conf.py
index d810858..01243de 100644
--- a/Doc/conf.py
+++ b/Doc/conf.py
@@ -239,5 +239,3 @@ c_allow_pre_v3 = True
 # bpo-40204: Disable warnings on Sphinx 2 syntax of the C domain since the
 # documentation is built with -W (warnings treated as errors).
 c_warn_on_allowed_pre_v3 = False
-
-strip_signature_backslash = True
diff --git a/Doc/library/asyncio-stream.rst b/Doc/library/asyncio-stream.rst
index 3558277..65f3d53 100644
--- a/Doc/library/asyncio-stream.rst
+++ b/Doc/library/asyncio-stream.rst
@@ -192,7 +192,7 @@ StreamReader
       can be read.  Use the :attr:`IncompleteReadError.partial`
       attribute to get the partially read data.
 
-   .. coroutinemethod:: readuntil(separator=b'\\n')
+   .. coroutinemethod:: readuntil(separator=b'\n')
 
       Read data from the stream until *separator* is found.
 
diff --git a/Doc/library/base64.rst b/Doc/library/base64.rst
index 35fb7b6..f1063a7 100644
--- a/Doc/library/base64.rst
+++ b/Doc/library/base64.rst
@@ -199,7 +199,7 @@ The modern interface provides:
    .. versionadded:: 3.4
 
 
-.. function:: a85decode(b, *, foldspaces=False, adobe=False, ignorechars=b' \\t\\n\\r\\v')
+.. function:: a85decode(b, *, foldspaces=False, adobe=False, ignorechars=b' \t\n\r\v')
 
    Decode the Ascii85 encoded :term:`bytes-like object` or ASCII string *b* and
    return the decoded :class:`bytes`.
diff --git a/Doc/library/difflib.rst b/Doc/library/difflib.rst
index aa08988..a5ee0fb 100644
--- a/Doc/library/difflib.rst
+++ b/Doc/library/difflib.rst
@@ -149,7 +149,7 @@ diffs. For comparing directories and files, see also, the :mod:`filecmp` module.
    contains a good example of its use.
 
 
-.. function:: context_diff(a, b, fromfile='', tofile='', fromfiledate='', tofiledate='', n=3, lineterm='\\n')
+.. function:: context_diff(a, b, fromfile='', tofile='', fromfiledate='', tofiledate='', n=3, lineterm='\n')
 
    Compare *a* and *b* (lists of strings); return a delta (a :term:`generator`
    generating the delta lines) in context diff format.
@@ -279,7 +279,7 @@ diffs. For comparing directories and files, see also, the :mod:`filecmp` module.
       emu
 
 
-.. function:: unified_diff(a, b, fromfile='', tofile='', fromfiledate='', tofiledate='', n=3, lineterm='\\n')
+.. function:: unified_diff(a, b, fromfile='', tofile='', fromfiledate='', tofiledate='', n=3, lineterm='\n')
 
    Compare *a* and *b* (lists of strings); return a delta (a :term:`generator`
    generating the delta lines) in unified diff format.
@@ -321,7 +321,7 @@ diffs. For comparing directories and files, see also, the :mod:`filecmp` module.
 
    See :ref:`difflib-interface` for a more detailed example.
 
-.. function:: diff_bytes(dfunc, a, b, fromfile=b'', tofile=b'', fromfiledate=b'', tofiledate=b'', n=3, lineterm=b'\\n')
+.. function:: diff_bytes(dfunc, a, b, fromfile=b'', tofile=b'', fromfiledate=b'', tofiledate=b'', n=3, lineterm=b'\n')
 
    Compare *a* and *b* (lists of bytes objects) using *dfunc*; yield a
    sequence of delta lines (also bytes) in the format returned by *dfunc*.
diff --git a/Doc/library/email.header.rst b/Doc/library/email.header.rst
index 07152c2..e093f13 100644
--- a/Doc/library/email.header.rst
+++ b/Doc/library/email.header.rst
@@ -116,7 +116,7 @@ Here is the :class:`Header` class description:
       if *s* is a byte string.
 
 
-   .. method:: encode(splitchars=';, \\t', maxlinelen=None, linesep='\\n')
+   .. method:: encode(splitchars=';, \t', maxlinelen=None, linesep='\n')
 
       Encode a message header into an RFC-compliant format, possibly wrapping
       long lines and encapsulating non-ASCII parts in base64 or quoted-printable
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 85e7d12..d22cc28 100644
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1387,7 +1387,7 @@ are always available.  They are listed here in alphabetical order.
       supported.
 
 
-.. function:: print(*objects, sep=' ', end='\\n', file=sys.stdout, flush=False)
+.. function:: print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)
 
    Print *objects* to the text stream *file*, separated by *sep* and followed
    by *end*.  *sep*, *end*, *file*, and *flush*, if present, must be given as keyword
diff --git a/Doc/library/http.cookies.rst b/Doc/library/http.cookies.rst
index 17792b2..a2c1eb0 100644
--- a/Doc/library/http.cookies.rst
+++ b/Doc/library/http.cookies.rst
@@ -93,7 +93,7 @@ Cookie Objects
    :meth:`value_decode` are inverses on the range of *value_decode*.
 
 
-.. method:: BaseCookie.output(attrs=None, header='Set-Cookie:', sep='\\r\\n')
+.. method:: BaseCookie.output(attrs=None, header='Set-Cookie:', sep='\r\n')
 
    Return a string representation suitable to be sent as HTTP headers. *attrs* and
    *header* are sent to each :class:`Morsel`'s :meth:`output` method. *sep* is used
diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index c125ec2..df812d6 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -1035,7 +1035,7 @@ Text I/O
       .. versionadded:: 3.7
 
 
-.. class:: StringIO(initial_value='', newline='\\n')
+.. class:: StringIO(initial_value='', newline='\n')
 
    A text stream using an in-memory text buffer.  It inherits
    :class:`TextIOBase`.
diff --git a/Doc/library/xml.dom.minidom.rst b/Doc/library/xml.dom.minidom.rst
index 20984b9..076cf34 100644
--- a/Doc/library/xml.dom.minidom.rst
+++ b/Doc/library/xml.dom.minidom.rst
@@ -180,7 +180,7 @@ module documentation.  This section lists the differences between the API and
    .. versionchanged:: 3.9
       The *standalone* parameter was added.
 
-.. method:: Node.toprettyxml(indent="\\t", newl="\\n", encoding=None, \
+.. method:: Node.toprettyxml(indent="\t", newl="\n", encoding=None, \
                              standalone=None)
 
    Return a pretty-printed version of the document. *indent* specifies the
diff --git a/Doc/tools/extensions/pyspecific.py b/Doc/tools/extensions/pyspecific.py
index 27004af..915b28a 100644
--- a/Doc/tools/extensions/pyspecific.py
+++ b/Doc/tools/extensions/pyspecific.py
@@ -418,12 +418,7 @@ class DeprecatedRemoved(Directive):
                                    translatable=False)
             node.append(para)
         env = self.state.document.settings.env
-        # deprecated pre-Sphinx-2 method
-        if hasattr(env, 'note_versionchange'):
-            env.note_versionchange('deprecated', version[0], node, self.lineno)
-        # new method
-        else:
-            env.get_domain('changeset').note_changeset(node)
+        env.get_domain('changeset').note_changeset(node)
         return [node] + messages
 
 
diff --git a/Doc/tools/extensions/suspicious.py b/Doc/tools/extensions/suspicious.py
index 9e814fb..ed7ec28 100644
--- a/Doc/tools/extensions/suspicious.py
+++ b/Doc/tools/extensions/suspicious.py
@@ -44,7 +44,6 @@ Copyright 2009 Gabriel A. Genellina
 import os
 import re
 import csv
-import sys
 
 from docutils import nodes
 from sphinx.builders import Builder
@@ -55,9 +54,7 @@ detect_all = re.compile(r'''
     :[a-zA-Z][a-zA-Z0-9]+| # :foo
     `|                     # ` (seldom used by itself)
     (?<!\.)\.\.[ \t]*\w+:  # .. foo: (but NOT ... else:)
-    ''', re.UNICODE | re.VERBOSE).finditer
-
-py3 = sys.version_info >= (3, 0)
+    ''', re.VERBOSE).finditer
 
 
 class Rule:
@@ -152,32 +149,15 @@ class CheckSuspiciousMarkupBuilder(Builder):
     def report_issue(self, text, lineno, issue):
         self.any_issue = True
         self.write_log_entry(lineno, issue, text)
-        if py3:
-            self.logger.warning('[%s:%d] "%s" found in "%-.120s"' %
+        self.logger.warning('[%s:%d] "%s" found in "%-.120s"' %
                                 (self.docname, lineno, issue, text))
-        else:
-            self.logger.warning(
-                '[%s:%d] "%s" found in "%-.120s"' % (
-                    self.docname.encode(sys.getdefaultencoding(),'replace'),
-                    lineno,
-                    issue.encode(sys.getdefaultencoding(),'replace'),
-                    text.strip().encode(sys.getdefaultencoding(),'replace')))
         self.app.statuscode = 1
 
     def write_log_entry(self, lineno, issue, text):
-        if py3:
-            f = open(self.log_file_name, 'a')
-            writer = csv.writer(f, dialect)
-            writer.writerow([self.docname, lineno, issue, text.strip()])
-            f.close()
-        else:
-            f = open(self.log_file_name, 'ab')
-            writer = csv.writer(f, dialect)
-            writer.writerow([self.docname.encode('utf-8'),
-                             lineno,
-                             issue.encode('utf-8'),
-                             text.strip().encode('utf-8')])
-            f.close()
+        f = open(self.log_file_name, 'a')
+        writer = csv.writer(f, dialect)
+        writer.writerow([self.docname, lineno, issue, text.strip()])
+        f.close()
 
     def load_rules(self, filename):
         """Load database of previously ignored issues.
@@ -188,10 +168,7 @@ class CheckSuspiciousMarkupBuilder(Builder):
         self.logger.info("loading ignore rules... ", nonl=1)
         self.rules = rules = []
         try:
-            if py3:
-                f = open(filename, 'r')
-            else:
-                f = open(filename, 'rb')
+            f = open(filename, 'r')
         except IOError:
             return
         for i, row in enumerate(csv.reader(f)):
@@ -203,10 +180,6 @@ class CheckSuspiciousMarkupBuilder(Builder):
                 lineno = int(lineno)
             else:
                 lineno = None
-            if not py3:
-                docname = docname.decode('utf-8')
-                issue = issue.decode('utf-8')
-                text = text.decode('utf-8')
             rule = Rule(docname, lineno, issue, text)
             rules.append(rule)
         f.close()