Changes to the documentation of normcase (GH-4725)

Doc/library/os.path.rst

@@ -87,7 +87,7 @@ the :mod:`glob` module.)
 .. function:: commonpath(paths)
 
    Return the longest common sub-path of each pathname in the sequence
-   *paths*.  Raise ValueError if *paths* contains both absolute and relative
+   *paths*.  Raise :exc:`ValueError` if *paths* contains both absolute and relative
    pathnames, or if *paths* is empty.  Unlike :func:`commonprefix`, this
    returns a valid path.
 
@@ -324,9 +324,9 @@ the :mod:`glob` module.)
 
 .. function:: normcase(path)
 
-   Normalize the case of a pathname.  On Unix and Mac OS X, this returns the
-   path unchanged; on case-insensitive filesystems, it converts the path to
-   lowercase.  On Windows, it also converts forward slashes to backward slashes.
+   Normalize the case of a pathname.  On Windows, convert all characters in the
+   pathname to lowercase, and also convert forward slashes to backward slashes.
+   On other operating systems, return the path unchanged.
    Raise a :exc:`TypeError` if the type of *path* is not ``str`` or ``bytes`` (directly
    or indirectly through the :class:`os.PathLike` interface).