bpo-40204: Allow pre-Sphinx 3 syntax in the doc (GH-21844) (GH-21901) (GH-21928)

* bpo-40204: Allow pre-Sphinx 3 syntax in the doc (GH-21844)

Enable Sphinx 3.2 "c_allow_pre_v3" option and disable the
c_warn_on_allowed_pre_v3 option to make the documentation compatible
with Sphinx 2 and Sphinx 3.

(cherry picked from commit 423e77d6de497931585d1883805a9e3fa4096b0b)

* bpo-40204: Fix Sphinx sytanx in howto/instrumentation.rst (GH-21858)

Use generic '.. object::' to declare markers, rather than abusing
'..  c:function::' which fails on Sphinx 3.

(cherry picked from commit 43577c01a2ab49122db696e9eaec6cb31d11cc81)

* bpo-40204: Fix duplicates in the documentation (GH-21857)

Fix two Sphinx 3 issues:

Doc/c-api/buffer.rst:304: WARNING: Duplicate C declaration, also defined in 'c-api/buffer'.
Declaration is 'PyBUF_ND'.

Doc/c-api/unicode.rst:1603: WARNING: Duplicate C declaration, also defined in 'c-api/unicode'.
Declaration is 'PyObject* PyUnicode_Translate(PyObject *str, PyObject *table, const char *errors)'.

(cherry picked from commit 46d10b1237c67ff8347f533eda6a5468d098f7eb)

* bpo-40204: Add :noindex: in the documentation (GH-21859)

Add :noindex: to duplicated documentation to fix "duplicate object
description" errors.

For example, fix this Sphinx 3 issue:

Doc/library/configparser.rst:1146: WARNING: duplicate object
description of configparser.ConfigParser.optionxform, other instance
in library/configparser, use :noindex: for one of them

(cherry picked from commit d3ded080482beae578faa704b13534a62d066f9f)

* bpo-40204, doc: Fix syntax of C variables (GH-21846)

For example, fix the following Sphinx 3 errors:

Doc/c-api/buffer.rst:102: WARNING: Error in declarator or parameters
Invalid C declaration: Expected identifier in nested name. [error at 5]
  void \*obj
  -----^

Doc/c-api/arg.rst:130: WARNING: Unparseable C cross-reference: 'PyObject*'
Invalid C declaration: Expected end of definition. [error at 8]
  PyObject*
  --------^

The modified documentation is compatible with Sphinx 2 and Sphinx 3.

(cherry picked from commit 474652fe9346382dbf793f20b671eb74668bebde)

* bpo-40204: Fix reference to terms in the doc (GH-21865)

Sphinx 3 requires to refer to terms with the exact case.

For example, fix the Sphinx 3 warning:

Doc/library/pkgutil.rst:71: WARNING: term Loader not found in case
sensitive match.made a reference to loader instead.

(cherry picked from commit bb0b08540cc93e56f3f1bde1b39ce086d9e35fe1)

* bpo-40204: Fix duplicated productionlist names in the doc (GH-21900)

Sphinx 3 disallows having more than one productionlist markup with
the same name. Simply remove names in this case, since names are not
shown anyway. For example, fix the Sphinx 3 warning:

Doc/reference/introduction.rst:96: duplicate token description
of *:name, other instance in reference/expressions

(cherry picked from commit 1abeda80f760134b4233608e2c288790f955b95a)
(cherry picked from commit 8f88190af529543c84d5dc78f19abbfd73335cf4)

1 files changed, 13 insertions, 13 deletions

diff --git a/Doc/c-api/memory.rst b/Doc/c-api/memory.rst
index 8a8542f..87425bc 100644
--- a/Doc/c-api/memory.rst
+++ b/Doc/c-api/memory.rst
@@ -109,7 +109,7 @@ zero bytes.
 
 .. c:function:: void* PyMem_RawMalloc(size_t n)
 
-   Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the
+   Allocates *n* bytes and returns a pointer of type :c:type:`void*` to the
    allocated memory, or ``NULL`` if the request fails.
 
    Requesting zero bytes returns a distinct non-``NULL`` pointer if possible, as
@@ -120,7 +120,7 @@ zero bytes.
 .. c:function:: void* PyMem_RawCalloc(size_t nelem, size_t elsize)
 
    Allocates *nelem* elements each whose size in bytes is *elsize* and returns
-   a pointer of type :c:type:`void\*` to the allocated memory, or ``NULL`` if the
+   a pointer of type :c:type:`void*` to the allocated memory, or ``NULL`` if the
    request fails. The memory is initialized to zeros.
 
    Requesting zero elements or elements of size zero bytes returns a distinct
@@ -180,7 +180,7 @@ The :ref:`default memory allocator <default-memory-allocators>` uses the
 
 .. c:function:: void* PyMem_Malloc(size_t n)
 
-   Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the
+   Allocates *n* bytes and returns a pointer of type :c:type:`void*` to the
    allocated memory, or ``NULL`` if the request fails.
 
    Requesting zero bytes returns a distinct non-``NULL`` pointer if possible, as
@@ -191,7 +191,7 @@ The :ref:`default memory allocator <default-memory-allocators>` uses the
 .. c:function:: void* PyMem_Calloc(size_t nelem, size_t elsize)
 
    Allocates *nelem* elements each whose size in bytes is *elsize* and returns
-   a pointer of type :c:type:`void\*` to the allocated memory, or ``NULL`` if the
+   a pointer of type :c:type:`void*` to the allocated memory, or ``NULL`` if the
    request fails. The memory is initialized to zeros.
 
    Requesting zero elements or elements of size zero bytes returns a distinct
@@ -233,14 +233,14 @@ The following type-oriented macros are provided for convenience.  Note  that
 .. c:function:: TYPE* PyMem_New(TYPE, size_t n)
 
    Same as :c:func:`PyMem_Malloc`, but allocates ``(n * sizeof(TYPE))`` bytes of
-   memory.  Returns a pointer cast to :c:type:`TYPE\*`.  The memory will not have
+   memory.  Returns a pointer cast to :c:type:`TYPE*`.  The memory will not have
    been initialized in any way.
 
 
 .. c:function:: TYPE* PyMem_Resize(void *p, TYPE, size_t n)
 
    Same as :c:func:`PyMem_Realloc`, but the memory block is resized to ``(n *
-   sizeof(TYPE))`` bytes.  Returns a pointer cast to :c:type:`TYPE\*`. On return,
+   sizeof(TYPE))`` bytes.  Returns a pointer cast to :c:type:`TYPE*`. On return,
    *p* will be a pointer to the new memory area, or ``NULL`` in the event of
    failure.
 
@@ -282,7 +282,7 @@ The :ref:`default object allocator <default-memory-allocators>` uses the
 
 .. c:function:: void* PyObject_Malloc(size_t n)
 
-   Allocates *n* bytes and returns a pointer of type :c:type:`void\*` to the
+   Allocates *n* bytes and returns a pointer of type :c:type:`void*` to the
    allocated memory, or ``NULL`` if the request fails.
 
    Requesting zero bytes returns a distinct non-``NULL`` pointer if possible, as
@@ -293,7 +293,7 @@ The :ref:`default object allocator <default-memory-allocators>` uses the
 .. c:function:: void* PyObject_Calloc(size_t nelem, size_t elsize)
 
    Allocates *nelem* elements each whose size in bytes is *elsize* and returns
-   a pointer of type :c:type:`void\*` to the allocated memory, or ``NULL`` if the
+   a pointer of type :c:type:`void*` to the allocated memory, or ``NULL`` if the
    request fails. The memory is initialized to zeros.
 
    Requesting zero elements or elements of size zero bytes returns a distinct
@@ -388,7 +388,7 @@ Customize Memory Allocators
 
    Enum used to identify an allocator domain. Domains:
 
-   .. c:var:: PYMEM_DOMAIN_RAW
+   .. c:macro:: PYMEM_DOMAIN_RAW
 
       Functions:
 
@@ -397,7 +397,7 @@ Customize Memory Allocators
       * :c:func:`PyMem_RawCalloc`
       * :c:func:`PyMem_RawFree`
 
-   .. c:var:: PYMEM_DOMAIN_MEM
+   .. c:macro:: PYMEM_DOMAIN_MEM
 
       Functions:
 
@@ -406,7 +406,7 @@ Customize Memory Allocators
       * :c:func:`PyMem_Calloc`
       * :c:func:`PyMem_Free`
 
-   .. c:var:: PYMEM_DOMAIN_OBJ
+   .. c:macro:: PYMEM_DOMAIN_OBJ
 
       Functions:
 
@@ -519,11 +519,11 @@ Customize pymalloc Arena Allocator
    | ``void free(void *ctx, size_t size, void *ptr)`` | free an arena                         |
    +--------------------------------------------------+---------------------------------------+
 
-.. c:function:: PyObject_GetArenaAllocator(PyObjectArenaAllocator *allocator)
+.. c:function:: void PyObject_GetArenaAllocator(PyObjectArenaAllocator *allocator)
 
    Get the arena allocator.
 
-.. c:function:: PyObject_SetArenaAllocator(PyObjectArenaAllocator *allocator)
+.. c:function:: void PyObject_SetArenaAllocator(PyObjectArenaAllocator *allocator)
 
    Set the arena allocator.