Fixed typoe on maintenance screen

Signed-off-by: snipe <[email protected]>

Author: snipe

resources/lang/en/general.php

@@ -355,6 +355,6 @@
     'checkin_tooltip' => 'Check this item in',
     'checkout_user_tooltip' => 'Check this item out to a user',
     'maintenance_mode'      => 'The service is temporarily unavailable for system updates. Please check back later.',
-    'maintenance_mode_title' => 'System Temporarily Unavilable',
+    'maintenance_mode_title' => 'System Temporarily Unavailable',
     'ldap_import'           => 'User password should not be managed by LDAP. (This allows you to send forgotten password requests.)',
 ];