doc PG 18 relnotes: move protocol version item to "server"

Reported-by: Jelte Fennema-Nio

Discussion: https://postgr.es/m/CAGECzQSTBgTsDJPxOHWKo7106-YnnYQGzpzNJdis+xTKGUhu2g@mail.gmail.com

doc/src/sgml/release-18.sgml

@@ -1113,7 +1113,7 @@ Make cancel request keys 256 bits (Heikki Linnakangas)
 </para>
 
 <para>
-This is enabled when the libpq client and server are Postgres 18 or later.
+This is only possible when the server and cliient support wire protocol version 3.2, introduced in this release.
 </para>
 </listitem>
 
@@ -2146,10 +2146,6 @@ Author: Robert Haas <rhaas@postgresql.org>
 Add function PQfullProtocolVersion() to report the full, including minor, protocol version number (Jacob Champion, Jelte Fennema-Nio)
 <ulink url="&commit_baseurl;cdb6b0fdb">&sect;</ulink>
 </para>
-
-<para>
-This release introduces wire protocol version 3.2.
-</para>
 </listitem>
 
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