doc: PG 16 relnotes, fix duplicate author and commit

Reported-by: Masahiko Sawada

Discussion: https://postgr.es/m/CAD21AoALE_joh=H-j5sdaAfDs=BXtCy6BQKYZBTi=neU8k0VFw@mail.gmail.com

Author: bmomjian

doc/src/sgml/release-16.sgml

@@ -1361,13 +1361,11 @@ Author: Andres Freund <andres@anarazel.de>
 2023-04-07 [be87200ef] Support invalidating replication slots due to horizon an
 Author: Andres Freund <andres@anarazel.de>
 2023-04-08 [26669757b] Handle logical slot conflicts on standby
-Author: Andres Freund <andres@anarazel.de>
-2023-04-08 [0fdab27ad] Allow logical decoding on standbys
 -->
 
 <listitem>
 <para>
-Allow logical decoding on standbys (Bertrand Drouvot, Andres Freund, Amit Khandekar, Bertrand Drouvot)
+Allow logical decoding on standbys (Bertrand Drouvot, Andres Freund, Amit Khandekar)
 </para>
 </listitem>