[3.12] gh-107801: Document io.TextIOWrapper.tell (#108265) (#108547)

(cherry picked from commit 38afa4af9bfc8297a5ee270c37f3f120a04297ea)

1 files changed, 9 insertions, 1 deletions

diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index 792bf43..25f4d0d 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -1054,13 +1054,21 @@ Text I/O
 
       * ``seek(0, SEEK_SET)``: Rewind to the start of the stream.
       * ``seek(cookie, SEEK_SET)``: Restore a previous position;
-        *cookie* **must be** a number returned by :meth:`!tell`.
+        *cookie* **must be** a number returned by :meth:`tell`.
       * ``seek(0, SEEK_END)``: Fast-forward to the end of the stream.
       * ``seek(0, SEEK_CUR)``: Leave the current stream position unchanged.
 
       Any other argument combinations are invalid,
       and may raise exceptions.
 
+   .. method:: tell()
+
+      Return the stream position as an opaque number.
+      The return value of :meth:`!tell` can be given as input to :meth:`seek`,
+      to restore a previous stream position.
+
+
+
 .. class:: StringIO(initial_value='', newline='\n')
 
    A text stream using an in-memory text buffer.  It inherits