docs: fix codecs table data

ISO-8859-4 is NOT for Baltic languages.  Also used more common spelling of Belarusian.

Author: mr-bronson

Doc/library/codecs.rst

@@ -1214,9 +1214,9 @@ particular, the following variants typically exist:
 +-----------------+--------------------------------+--------------------------------+
 | iso8859_3       | iso-8859-3, latin3, L3         | Esperanto, Maltese             |
 +-----------------+--------------------------------+--------------------------------+
-| iso8859_4       | iso-8859-4, latin4, L4         | Baltic languages               |
+| iso8859_4       | iso-8859-4, latin4, L4         | Northern Europe                |
 +-----------------+--------------------------------+--------------------------------+
-| iso8859_5       | iso-8859-5, cyrillic           | Bulgarian, Byelorussian,       |
+| iso8859_5       | iso-8859-5, cyrillic           | Belarusian, Bulgarian,         |
 |                 |                                | Macedonian, Russian, Serbian   |
 +-----------------+--------------------------------+--------------------------------+
 | iso8859_6       | iso-8859-6, arabic             | Arabic                         |