PG 18 relnotes and RC1

If RC1 is supposed to actually match a release candidate, we have two
problems with its release notes.  

First, the release notes are incomplete because the "new features and
enhancements" and "Acknowledgments" sections are empty.

Second, the release note item added by this commit:

	commit d1073c3b4cc
	Author: Peter Eisentraut <peter@eisentraut.org>
	Date:   Fri Aug 29 10:18:10 2025 +0200
	
	    doc PG 18 relnotes: Add migration note about tsearch
	
	    Document the small migration hazard introduced in commit fb1a18810f0,
	    as suggested there.
	
	    Reviewed-by: Daniel Verite <daniel@manitou-mail.org>
	    Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
	    Discussion: https://www.postgresql.org/message-id/flat/653f3b84-fc87-45a7-9a0c-bfb4fcab3e7d%40eisentraut.org

added this text to the release notes:

	<!--
	Author: Peter Eisentraut <peter@eisentraut.org>
-->	2024-12-17 [fb1a18810f0] Remove ts_locale.c's lowerstr()
	-->
	
	    <listitem>
	    <para>
	    The locale implementation underlying full-text search was improved.  It
	    now observes the locale provider configured for the database for case
	    conversions.  It was previously hardcoded to use libc.  In database
	    clusters that use a locale provider other than libc (that is, ICU or
	    builtin) and where the locale configured through that locale provider
	    behaves differently from the LC_CTYPE setting configured for the database,
	    this could cause changes in behavior of some functions related to
	    full-text search as well as the pg_trgm extension.  When upgrading such
	    database clusters using pg_upgrade, it is recommended to reindex all
	    indexes related to full-text search and pg_trgm after the upgrade.
-->	    <ulink url="&commit_baseurl;fb1a18810f0">&sect;</ulink>
	    </para>
	    </listitem>

Unfortunately src/tools/add_commit_links.pl can't process the <ulink>
and throws an error because the previous line does not end with a
parenthesis.  If I add "()" after the last line in the text block, it
works fine, but obviously this is not acceptable.  I can add spaces to
two lines and that fixes it:

	<!--
	Author: Peter Eisentraut <peter@eisentraut.org>
-->	2024-12-17 [ fb1a18810f0] Remove ts_locale.c's lowerstr()
	-->
	
	    <listitem>
	    <para>
	    The locale implementation underlying full-text search was improved.  It
	    now observes the locale provider configured for the database for case
	    conversions.  It was previously hardcoded to use libc.  In database
	    clusters that use a locale provider other than libc (that is, ICU or
	    builtin) and where the locale configured through that locale provider
	    behaves differently from the LC_CTYPE setting configured for the database,
	    this could cause changes in behavior of some functions related to
	    full-text search as well as the pg_trgm extension.  When upgrading such
	    database clusters using pg_upgrade, it is recommended to reindex all
	    indexes related to full-text search and pg_trgm after the upgrade.
-->	    <ulink  url="&commit_baseurl;fb1a18810f0">&sect;</ulink>
	    </para>
	    </listitem>

I can commit this once our RC1 git tree freeze is over.  Is that Tuesday?

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Do not let urgent matters crowd out time for investment in the future.