doc: Remove incorrect description about dropping replication slots.

pg_drop_replication_slot() can drop replication slots created on
a different database than the one where it is executed. This behavior
has been in place since PostgreSQL 9.4, when pg_drop_replication_slot()
was introduced.

However, commit ff539d mistakenly added the following incorrect
description in the documentation:

     For logical slots, this must be called when connected to
     the same database the slot was created on.

This commit removes that incorrect statement. A similar mistake was
also present in the documentation for the DROP_REPLICATION_SLOT
command, which has now been corrected as well.

Back-patch to all supported versions.

Author: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/OSCPR01MB14966C6BE304B5BB2E58D4009F5DE2@OSCPR01MB14966.jpnprd01.prod.outlook.com
Backpatch-through: 13

doc/src/sgml/func.sgml

@@ -29045,8 +29045,7 @@ postgres=# SELECT '0/0'::pg_lsn + pd.segment_number * ps.setting::int + :offset
        <para>
         Drops the physical or logical replication slot
         named <parameter>slot_name</parameter>. Same as replication protocol
-        command <literal>DROP_REPLICATION_SLOT</literal>. For logical slots, this must
+        command <literal>DROP_REPLICATION_SLOT</literal>.
-        be called while connected to the same database the slot was created on.
        </para></entry>
       </row>
 

doc/src/sgml/protocol.sgml

@@ -2660,8 +2660,6 @@ psql "dbname=postgres replication=database" -c "IDENTIFY_SYSTEM;"
      <listitem>
       <para>
        Drops a replication slot, freeing any reserved server-side resources.
-       If the slot is a logical slot that was created in a database other than
-       the database the walsender is connected to, this command fails.
       </para>
 
       <variablelist>