pgsql: GIN documentation and slightly improving GiST docs.

Log Message:
-----------
GIN documentation and slightly improving GiST docs.
Thanks to  Christopher Kings-Lynne <chris.kingslynne@gmail.com> for
initial version and Jeff Davis <pgsql@j-davis.com> for inspection

Modified Files:
--------------
    pgsql/doc/src/sgml:
        config.sgml (r1.85 -> r1.86)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml.diff?r1=1.85&r2=1.86)
        filelist.sgml (r1.46 -> r1.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/filelist.sgml.diff?r1=1.46&r2=1.47)
        geqo.sgml (r1.36 -> r1.37)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/geqo.sgml.diff?r1=1.36&r2=1.37)
        indices.sgml (r1.61 -> r1.62)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/indices.sgml.diff?r1=1.61&r2=1.62)
        mvcc.sgml (r2.58 -> r2.59)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/mvcc.sgml.diff?r1=2.58&r2=2.59)
        xindex.sgml (r1.45 -> r1.46)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/xindex.sgml.diff?r1=1.45&r2=1.46)
    pgsql/doc/src/sgml/ref:
        create_opclass.sgml (r1.15 -> r1.16)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_opclass.sgml.diff?r1=1.15&r2=1.16)

Added Files:
-----------
    pgsql/doc/src/sgml:
        gin.sgml (r2.1)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/gin.sgml?rev=2.1&content-type=text/x-cvsweb-markup)