doc: Simplify COMMENT and SECURITY LABEL documentation

Just say that objects that reside in schemas can be schema-qualified.
Don't list all possible such objects.  The existing lists weren't
complete anyway.

Discussion: https://www.postgresql.org/message-id/flat/b2ec2234-67fe-d861-5cea-f526cd18c086%40enterprisedb.com

doc/src/sgml/ref/comment.sgml

@@ -129,10 +129,8 @@ COMMENT ON
     <term><replaceable class="parameter">trigger_name</replaceable></term>
     <listitem>
      <para>
-      The name of the object to be commented.  Names of tables,
-      aggregates, collations, conversions, domains, foreign tables, functions,
-      indexes, operators, operator classes, operator families, procedures, routines, sequences,
-      statistics, text search objects, types, and views can be
+      The name of the object to be commented.  Names of objects that reside in
+      schemas (tables, functions, etc.) can be
       schema-qualified. When commenting on a column,
       <replaceable class="parameter">relation_name</replaceable> must refer
       to a table, view, composite type, or foreign table.

doc/src/sgml/ref/security_label.sgml

@@ -99,9 +99,8 @@ SECURITY LABEL [ FOR <replaceable class="parameter">provider</replaceable> ] ON
     <term><replaceable class="parameter">routine_name</replaceable></term>
     <listitem>
      <para>
-      The name of the object to be labeled.  Names of tables,
-      aggregates, domains, foreign tables, functions, procedures, routines, sequences, types, and
-      views can be schema-qualified.
+      The name of the object to be labeled.  Names of objects that reside in
+      schemas (tables, functions, etc.) can be schema-qualified.
      </para>
     </listitem>
    </varlistentry>