Add padding to actions of completion

The actions are rendered in a separated list and no more as items of the
dropdown so we must replicate the same padding for visual consistency.

Closes #14584

sao/src/sao.less

@@ -134,6 +134,7 @@ html[theme="default"] {
         .action a {
             clear: both;
             display: block;
+            padding: 3px 0px;
         }
     }
 }