pgsql: doc: Add missing cross-links in system catalog documentation

doc: Add missing cross-links in system catalog documentation

This makes the first mention of a system catalog or view in each
paragraph in the system system catalog and view documentation pages
hyperlinks, for easier navigation.

Also linkify the first mention of pg_hba.conf in pg_hba_file_rules, as
that's more specific and easier to spot than the link to the client
authentication chapter.

Author: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://www.postgresql.org/message-id/flat/87mu5xqc11.fsf@wibble.ilmari.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/cb6eb4a09e8adf3cc25e8eff9fdd43d8d9cd9c86

Modified Files
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doc/src/sgml/catalogs.sgml | 122 ++++++++++++++++++++++++---------------------
1 file changed, 66 insertions(+), 56 deletions(-)