pgsql: Improve stylistic consistency of descriptions of built-in objects

Log Message:
-----------
Improve stylistic consistency of descriptions of built-in objects by avoiding
initcap style --- the vast majority of the existing descriptions do not use
an initial cap.  I didn't change places where the first word was all-cap.

initdb not forced because this doesn't change any regression test results.

Modified Files:
--------------
    pgsql/src/backend/snowball:
        snowball.sql.in (r1.3 -> r1.4)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/snowball/snowball.sql.in?r1=1.3&r2=1.4)
        snowball_func.sql.in (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/snowball/snowball_func.sql.in?r1=1.1&r2=1.2)
    pgsql/src/include/catalog:
        pg_database.h (r1.43 -> r1.44)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_database.h?r1=1.43&r2=1.44)
        pg_language.h (r1.30 -> r1.31)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_language.h?r1=1.30&r2=1.31)
        pg_namespace.h (r1.21 -> r1.22)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_namespace.h?r1=1.21&r2=1.22)
        pg_proc.h (r1.466 -> r1.467)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h?r1=1.466&r2=1.467)
        pg_ts_template.h (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_ts_template.h?r1=1.1&r2=1.2)
        pg_type.h (r1.187 -> r1.188)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_type.h?r1=1.187&r2=1.188)