pgsql: Change descriptions of entity and tag objects to "XML entity" and

Log Message:
-----------
Change descriptions of entity and tag objects to "XML entity" and "XML tag".
Allow tag and entity names that follow XML rules. Provide for hexadecimal
as well as decimal numeric entities. Adjust code names to coincide with
new descriptions.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        textsearch.sgml (r1.36 -> r1.37)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/textsearch.sgml?r1=1.36&r2=1.37)
    pgsql/src/backend/tsearch:
        wparser_def.c (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/tsearch/wparser_def.c?r1=1.10&r2=1.11)
    pgsql/src/test/regress/expected:
        tsearch.out (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/tsearch.out?r1=1.8&r2=1.9)