Mk: unregister expired PostgreSQL 9.6

Update an IGNORE message, leave examples at the top of pgsql.mk
alone for now.

Mk/Uses/pgsql.mk

@@ -39,7 +39,7 @@ _INCLUDE_USES_PGSQL_MK=	yes
 
 # When adding a version, please keep the comment in
 # Mk/bsd.default-versions.mk in sync.
-VALID_PGSQL_VER=	9.6 10 11 12 13 14
+VALID_PGSQL_VER=	10 11 12 13 14
 
 # Override non-default LIBVERS like this:
 #PGSQL99_LIBVER=6
@@ -63,7 +63,7 @@ PGSQL_DEFAULT?=	${$w_PGSQL_VER:C,^.,&.,}
 .  endfor
 
 .  ifdef DEFAULT_PGSQL_VER && WITH_PGSQL_VER
-IGNORE=		will not allow setting both DEFAULT_PGSQL_VER and WITH_PGSQL_VER.  Use DEFAULT_VERSIONS=pgsql=9.6 instead
+IGNORE=		will not allow setting both DEFAULT_PGSQL_VER and WITH_PGSQL_VER.  Use DEFAULT_VERSIONS=pgsql=13 instead
 .  endif
 
 # Setting/finding PostgreSQL version we want.

Mk/bsd.default-versions.mk

@@ -105,7 +105,7 @@ _PERL5_FROM_BIN!=	${LOCALBASE}/bin/perl -e 'printf "%vd\n", $$^V;'
 _EXPORTED_VARS+=	_PERL5_FROM_BIN
 PERL5_DEFAULT:=		${_PERL5_FROM_BIN:R}
 .endif
-# Possible values: 9.6, 10, 11, 12, 13, 14
+# Possible values: 10, 11, 12, 13, 14
 PGSQL_DEFAULT?=		13
 # Possible values: 7.4, 8.0, 8.1
 PHP_DEFAULT?=		8.0