doc: PG 16 relnotes, fix PREPARE/EXECUTE wording

Reported-by: Erik Rijkers

Discussion: https://postgr.es/m/73f361d0-237e-3413-224b-86ab6b71a3dd@xs4all.nl

Author: bmomjian

doc/src/sgml/release-16.sgml

@@ -2868,7 +2868,7 @@ Allow auto_explain to log values passed to parameterized statements (Dagfinn Ilm
 </para>
 
 <para>
-This affects queries using server-side PRAPARE/EXECUTE and client-side parse/bind.  Logging is controlled by auto_explain.log_parameter_max_length;  by default query parameters will
+This affects queries using server-side PREPARE/EXECUTE and client-side parse/bind.  Logging is controlled by auto_explain.log_parameter_max_length;  by default query parameters will
 be logged with no length restriction.
 </para>
 </listitem>