postgresql database fts - add to CHANGES and add url to admin.

Missed commiting the CHANGES and add somewhat useful link to creating
config that ignores accent marks.

Author: rouilj

CHANGES.txt

@@ -124,6 +124,8 @@ Features:
 - Added xapian indexer to Docker container. (John Rouillard)
 - Add support for indexer type native-fts to use FTS5 for sqlite
   databases. (John Rouillard)
+- Add support for indexer type native-fts to use PostreSQL's full text
+  search. (John Rouillard)
 - Add better error display to the user. Needed to expose errors in fts5
   search syntax to the user while also displaying the template page
   structure. (John Rouillard)

doc/admin_guide.txt

@@ -424,7 +424,9 @@ Also there are various `dictionaries`_ that allow you to:
 .. _dictionaries: https://www.postgresql.org/docs/14/textsearch-dictionaries.html
 
 Use of these is beyond this documentation. Please visit the
-appropriate PostgreSQL documents.
+appropriate PostgreSQL documents. The following my also be helpful:
+
+* http://rachbelaid.com/postgres-full-text-search-is-good-enough/
 
 Ranking information is not used in this implementation. Also stop
 words set in config.ini are ignored. These are areas for improvement.