Improve terminology

Use "prepared transaction" instead of "two-phrase transaction".  This
is in line with 0e60a50.

Author: petere

doc/src/sgml/ref/pg_recvlogical.sgml

@@ -75,7 +75,7 @@ PostgreSQL documentation
 
        <para>
         The <option>--two-phase</option> can be specified with
-        <option>--create-slot</option> to enable two-phase decoding.
+        <option>--create-slot</option> to enable decoding of prepared transactions.
        </para>
       </listitem>
      </varlistentry>
@@ -273,7 +273,7 @@ PostgreSQL documentation
        <term><option>--two-phase</option></term>
        <listitem>
        <para>
-        Enables two-phase decoding. This option should only be specified with
+        Enables decoding of prepared transactions. This option may only be specified with
         <option>--create-slot</option>
        </para>
        </listitem>

src/bin/pg_basebackup/pg_recvlogical.c

@@ -94,7 +94,7 @@ usage(void)
 	printf(_("  -s, --status-interval=SECS\n"
 			 "                         time between status packets sent to server (default: %d)\n"), (standby_message_timeout / 1000));
 	printf(_("  -S, --slot=SLOTNAME    name of the logical replication slot\n"));
-	printf(_("  -t, --two-phase        enable two-phase decoding when creating a slot\n"));
+	printf(_("  -t, --two-phase        enable decoding of prepared transactions when creating a slot\n"));
 	printf(_("  -v, --verbose          output verbose messages\n"));
 	printf(_("  -V, --version          output version information, then exit\n"));
 	printf(_("  -?, --help             show this help, then exit\n"));