Always use pipe separator for notes in warning log

Warning reasons might contain parentheses so it may be ambiguous, and
deletions are already logged with the pipe character, which is also used
when setting the warning, anyway.

src/warnings.py

@@ -890,7 +890,7 @@ def fwarn(cli, nick, chan, rest):
         if var.LOG_CHANNEL:
             log_reason = reason
             if notes is not None:
-                log_reason += " ({0})".format(notes)
+                log_reason += " | " + notes
             if expires is None:
                 log_length = messages["fwarn_log_add_noexpiry"]
             else: