gh-110383: Improve accuracy of str.split() and str.rsplit() docstrings

[erlend-aasland]

Mention split direction in the docstring body,
instead of in the 'maxsplit' param docstring.

• Issue: Issues from docs@python.org #110383

[erlend-aasland]

Alternative to #111247 and #113353.

[hugovk]

Looks good:

❯ ./python.exe Python 3.13.0a2+ (heads/splitter!-dirty:c50dd463dd, Dec 21 2023, 14:51:45) [Clang 15.0.0 (clang-1500.1.0.2.5)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> help(str().split) Help on built-in function split: split(sep=None, maxsplit=-1) method of builtins.str instance Return a list of the substrings in the string, using sep as the separator string. sep The separator used to split the string. When set to None (the default value), will split on any whitespace character (including \n \r \t \f and spaces) and will discard empty strings from the result. maxsplit Maximum number of splits. -1 (the default value) means no limit. Splitting starts at the front of the string and works to the end. Note, str.split() is mainly useful for data that has been intentionally delimited. With natural text that includes punctuation, consider using the regular expression module. >>> help(str().rsplit) Help on built-in function rsplit: rsplit(sep=None, maxsplit=-1) method of builtins.str instance Return a list of the substrings in the string, using sep as the separator string. sep The separator used to split the string. When set to None (the default value), will split on any whitespace character (including \n \r \t \f and spaces) and will discard empty strings from the result. maxsplit Maximum number of splits. -1 (the default value) means no limit. Splitting starts at the end of the string and works to the front. >>>

Thanks everyone!

[bedevere-app]

GH-113379 is a backport of this pull request to the 3.12 branch.

[bedevere-app]

GH-113380 is a backport of this pull request to the 3.11 branch.