Hide change input button until hover

lib/devtools.js

@@ -24,6 +24,13 @@ customElements.define('developer-tooling', class extends HTMLElement {
             color: red;
           }
 
+          #server-message:hover #change-port-show {
+            display: inline-block;
+          }
+          #change-port-show {
+            display: none;
+          }
+
           .hidden {
             display: none;
           }