Fix accidental revert by Evan in b4da5f37.

plugins/Blacklist/BlacklistPlugin.php

@@ -511,7 +511,7 @@ class BlacklistPlugin extends Plugin
             if (!empty($nickname)) {
                 if (!$this->_checkNickname($nickname)) {
                     // TRANS: Exception thrown trying to post a notice while having a blocked nickname. %s is the blocked nickname.
-                    $msg = sprintf(_m("Notices from nickname \"%s\" disallowed."),
+                    $msg = sprintf(_m("Notices from nickname \"%s\" are disallowed."),
                                    $nickname);
                     throw new ClientException($msg);
                 }