hide page status alert when editing with HackMD

resource/styles/scss/_on-edit.scss

@@ -290,6 +290,11 @@ body.on-edit {
         right: 0;
       }
     }
+
+    // hide #page-status-alert
+    #page-status-alert {
+      display: none;
+    }
   }
 
 }