Migrate missing strings from Manage Containers panel to i18n

src/_locales/en/messages.json

@@ -119,6 +119,9 @@
   "manageContainers": {
     "message": "Manage Containers"
   },
+  "newContainer": {
+    "message": "New Container"
+  },
   "hideThisContainer": {
     "message": "Hide This Container"
   },

src/js/popup.js

@@ -988,7 +988,7 @@ Logic.registerPanel(MANAGE_CONTAINERS_PICKER, {
       });
       this._listenerSet = true;
     }
-    document.getElementById("picker-title").textContent = "Manage Containers";
+    document.getElementById("picker-title").textContent = browser.i18n.getMessage("manageContainers");
     const fragment = document.createDocumentFragment();
     const pickedFunction = function (identity) {
       Logic.showPanel(P_CONTAINER_EDIT, identity);
@@ -1000,7 +1000,7 @@ Logic.registerPanel(MANAGE_CONTAINERS_PICKER, {
           <td>
             <div class="menu-icon"><img alt="New Container" src="/img/new-16.svg" />
             </div>
-            <span class="menu-text">New Container</span>
+            <span class="menu-text">${ browser.i18n.getMessage("newContainer") }</span>
           </td>
         </tr>
       </table>

src/popup.html

@@ -177,7 +177,7 @@
         </tr>
       </table>
     </div>
-    <div class="bottom-btn keyboard-nav hover-highlight" id="manage-containers-link" tabindex="0" data-i18n-message-id="manageContainers">Manage Containers</div>
+    <div class="bottom-btn keyboard-nav hover-highlight" id="manage-containers-link" tabindex="0" data-i18n-message-id="manageContainers"></div>
   </div>