[3.12] gh-101699: Explain using Match.expand with \g<0> (GH-101701) (GH-115583)

Update documentation for re library to explain that a backreference `\g<0>` is
expanded to the entire string when using Match.expand().
Note that numeric backreferences to group 0 (`\0`) are not supported.

(cherry picked from commit d2d7808853)

Co-authored-by: Stevoisiak <S.Vascellaro@gmail.com>
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
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Miss Islington (bot) 2024-02-17 14:04:09 +01:00 committed by GitHub
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@ -1338,7 +1338,8 @@ when there is no match, you can test whether there was a match with a simple
Escapes such as ``\n`` are converted to the appropriate characters,
and numeric backreferences (``\1``, ``\2``) and named backreferences
(``\g<1>``, ``\g<name>``) are replaced by the contents of the
corresponding group.
corresponding group. The backreference ``\g<0>`` will be
replaced by the entire match.
.. versionchanged:: 3.5
Unmatched groups are replaced with an empty string.