gh-102899: Fix doc link for getting filesystem error handler (#102901)

Author: ogayot

Doc/library/sys.rst

@@ -697,7 +697,7 @@ always available.
    the encoding used with the :term:`filesystem error handler <filesystem
    encoding and error handler>` to convert between Unicode filenames and bytes
    filenames. The filesystem error handler is returned from
-   :func:`getfilesystemencoding`.
+   :func:`getfilesystemencodeerrors`.
 
    For best compatibility, str should be used for filenames in all cases,
    although representing filenames as bytes is also supported. Functions