gh-82849: revise intro to os.path.rst (GH-32232)

* revise the first paragraph of docs for os.path
* add a mention of `os.PathLike` protocol
* remove warnings rendered irrelevant by :pep:`383` and :pep:`529`

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Author: jdevries3133

Doc/library/os.path.rst

@@ -11,16 +11,10 @@
 
 --------------
 
-This module implements some useful functions on pathnames. To read or
-write files see :func:`open`, and for accessing the filesystem see the
-:mod:`os` module. The path parameters can be passed as either strings,
-or bytes. Applications are encouraged to represent file names as
-(Unicode) character strings. Unfortunately, some file names may not be
-representable as strings on Unix, so applications that need to support
-arbitrary file names on Unix should use bytes objects to represent
-path names. Vice versa, using bytes objects cannot represent all file
-names on Windows (in the standard ``mbcs`` encoding), hence Windows
-applications should use string objects to access all files.
+This module implements some useful functions on pathnames. To read or write
+files see :func:`open`, and for accessing the filesystem see the :mod:`os`
+module. The path parameters can be passed as strings, or bytes, or any object
+implementing the :class:`os.PathLike` protocol.
 
 Unlike a unix shell, Python does not do any *automatic* path expansions.
 Functions such as :func:`expanduser` and :func:`expandvars` can be invoked
@@ -38,7 +32,6 @@ the :mod:`glob` module.)
    their parameters.  The result is an object of the same type, if a path or
    file name is returned.
 
-
 .. note::
 
    Since different operating systems have different path name conventions, there

Misc/NEWS.d/next/Documentation/2022-04-01-09-28-31.bpo-38668.j4mrqW.rst

@@ -0,0 +1,3 @@
+Update the introduction to documentation for :mod:`os.path` to remove
+warnings that became irrelevant after the implementations of :pep:`383` and
+:pep:`529`.