This reverts
d8aa21b74ff, which was added for the PG 18 release notes,
and adjusts the PG 18 release notes for this change. This is necessary
since the "xreflabel" affected other references to these chapters.
Reported-by: Robert Treat
Author: Robert Treat
Discussion: https://postgr.es/m/CABV9wwNEZDdp5QtrW5ut0H+MOf6U1PvrqBqmgSTgcixqk+Q73A@mail.gmail.com
Backpatch-through: 18
<!-- doc/src/sgml/libpq.sgml -->
-<chapter id="libpq" xreflabel="libpq">
+<chapter id="libpq">
<title><application>libpq</application> — C Library</title>
<indexterm zone="libpq">
<!-- doc/src/sgml/plpython.sgml -->
-<chapter id="plpython" xreflabel="PL/Python">
+<chapter id="plpython">
<title>PL/Python — Python Procedural Language</title>
<indexterm zone="plpython"><primary>PL/Python</primary></indexterm>