[BS5] change bootstrap general

data/web/templates/edit/relayhost.twig

@@ -9,7 +9,7 @@
     <label class="control-label col-sm-2" for="hostname">{{ lang.add.hostname }}</label>
     <div class="col-sm-10">
       <input type="text" class="form-control" name="hostname" value="{{ result.hostname }}" required>
-      <p class="help-block">{{ lang.add.relayhost_wrapped_tls_info|raw }}</p>
+      <p class="text-muted">{{ lang.add.relayhost_wrapped_tls_info|raw }}</p>
     </div>
   </div>
   <div class="form-group">