Fix grammatical error in stringprep documentation (python#108414)

Remove the word "them", which didn't make grammatical sense.

Co-authored-by: KRAAI, MATTHEW [VISUS] <[email protected]>

Doc/library/stringprep.rst

@@ -27,7 +27,7 @@ procedure are part of the profile. One example of a ``stringprep`` profile is
 ``nameprep``, which is used for internationalized domain names.
 
 The module :mod:`stringprep` only exposes the tables from :rfc:`3454`. As these
-tables would be very large to represent them as dictionaries or lists, the
+tables would be very large to represent as dictionaries or lists, the
 module uses the Unicode character database internally. The module source code
 itself was generated using the ``mkstringprep.py`` utility.