Reword the phrase on zero replication_timeout in the docs.

doc/src/sgml/config.sgml

@@ -2030,7 +2030,8 @@ SET ENABLE_SEQSCAN TO OFF;
         Terminate replication connections that are inactive longer
         than the specified number of milliseconds. This is useful for
         the primary server to detect a standby crash or network outage.
-        A value of zero means wait forever.  This parameter can only be set in
+        A value of zero disables the timeout mechanism.  This parameter
+        can only be set in
         the <filename>postgresql.conf</> file or on the server command line.
         The default value is 60 seconds.
        </para>