doc: Fix parameter name for pg_create_logical_replication_slot()

The parameter controlling if two-phase transactions can be decoded was
named "two_phase" in the documentation while its procedure defines
"twophase".

Author: Florin Irion
Discussion: https://postgr.es/m/5eeabd10-1aff-ea61-f92d-9fa0d9a7e207@gmail.com
Backpatch-through: 14

Author: michaelpq

doc/src/sgml/func.sgml

@@ -26380,7 +26380,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset((pg_backup_stop()).lsn);
         <indexterm>
          <primary>pg_create_logical_replication_slot</primary>
         </indexterm>
-        <function>pg_create_logical_replication_slot</function> ( <parameter>slot_name</parameter> <type>name</type>, <parameter>plugin</parameter> <type>name</type> <optional>, <parameter>temporary</parameter> <type>boolean</type>, <parameter>two_phase</parameter> <type>boolean</type> </optional> )
+        <function>pg_create_logical_replication_slot</function> ( <parameter>slot_name</parameter> <type>name</type>, <parameter>plugin</parameter> <type>name</type> <optional>, <parameter>temporary</parameter> <type>boolean</type>, <parameter>twophase</parameter> <type>boolean</type> </optional> )
         <returnvalue>record</returnvalue>
         ( <parameter>slot_name</parameter> <type>name</type>,
         <parameter>lsn</parameter> <type>pg_lsn</type> )
@@ -26393,7 +26393,7 @@ postgres=# SELECT * FROM pg_walfile_name_offset((pg_backup_stop()).lsn);
         the slot should not be permanently stored to disk and is only meant
         for use by the current session. Temporary slots are also
         released upon any error. The optional fourth parameter,
-        <parameter>two_phase</parameter>, when set to true, specifies
+        <parameter>twophase</parameter>, when set to true, specifies
         that the decoding of prepared transactions is enabled for this
         slot. A call to this function has the same effect as the replication
         protocol command <literal>CREATE_REPLICATION_SLOT ... LOGICAL</literal>.