doc: PG 16 relnotes: adjust outer/full hash join parallelization

Reported-by: David Rowley

Discussion: https://postgr.es/m/CAApHDvph4djrP+zjOK67VcgbB_p9Zn8QoO7Qctt4oQgUC_ejEw@mail.gmail.com

Author: bmomjian

doc/src/sgml/release-16.sgml

@@ -322,7 +322,7 @@ Author: Thomas Munro <tmunro@postgresql.org>
 
 <listitem>
 <para>
-Allow outer and full joins to be performed in parallel (Melanie Plageman, Thomas Munro)
+Allow parallelization of FULL and internal right OUTER hash joins (Melanie Plageman, Thomas Munro)
 </para>
 </listitem>