Other: Add whitespace rules from GJS Style Guide and fix complaints

Add whitespace rules from GJS Style Guide to ESLint config and fix new
complaints.
See here for the GJS Style guide whitespace section:
https://gjs.guide/guides/gjs/style-guide.html#whitespace

.eslintrc.yml

@@ -20,6 +20,28 @@ rules:
   no-unused-vars:
     - error
     - argsIgnorePattern: "^_"
+  # Rules from GJS Style Guide regarding whitespace.
+  # See here: https://gjs.guide/guides/gjs/style-guide.html#whitespace
+  func-call-spacing:
+    - error
+    - never
+  array-bracket-spacing:
+    - error
+    - never
+  space-before-function-paren:
+    - error
+    - never
+  space-before-blocks:
+    - error
+    - always
+  key-spacing:
+    - error
+    - beforeColon: false
+      afterColon: true
+      mode: strict
+  object-curly-spacing:
+    - error
+    - always
 globals:
   imports: readonly
   log: readonly

src/extension.js

@@ -26,7 +26,7 @@ class Extension {
         this.#overwritePanelAddToPanelBox();
 
         // Handle changes of configured box orders.
-        this._settingsHandlerIds = [ ];
+        this._settingsHandlerIds = [];
 
         const addConfiguredBoxOrderChangeHandler = (box) => {
             let handlerId = this.settings.connect(`changed::${box}-box-order`, () => {
@@ -98,7 +98,7 @@ class Extension {
         };
 
         // Overwrite `Panel._addToPanelBox`.
-        Panel.Panel.prototype._addToPanelBox = function (role, indicator, position, box) {
+        Panel.Panel.prototype._addToPanelBox = function(role, indicator, position, box) {
             // Simply call the original `_addToPanelBox` and order the top bar
             // and handle new items afterwards.
             this._originalAddToPanelBox(role, indicator, position, box);

src/extensionModules/BoxOrderManager.js

@@ -80,7 +80,7 @@ var BoxOrderManager = GObject.registerClass({
             }
         } else {
             // Otherwise create a new array.
-            this._appIndicatorItemApplicationRoleMap.set(application, [ role ]);
+            this._appIndicatorItemApplicationRoleMap.set(application, [role]);
         }
 
         // Return the placeholder.
@@ -97,7 +97,7 @@ var BoxOrderManager = GObject.registerClass({
      * resolved/replaced to/with actual roles.
      */
     #resolveAppIndicatorPlaceholders(boxOrder) {
-        let resolvedBoxOrder = [ ];
+        let resolvedBoxOrder = [];
         for (const role of boxOrder) {
             // If the role isn't a placeholder, just add it to the resolved box
             // order.
@@ -171,7 +171,7 @@ var BoxOrderManager = GObject.registerClass({
         // Go through the box order and only add items to the valid box order,
         // where their indicator is present in the Gnome Shell top bar
         // currently.
-        let validBoxOrder = [ ];
+        let validBoxOrder = [];
         for (const role of boxOrder) {
             // Get the indicator container associated with the current role.
             const associatedIndicatorContainer = Main.panel.statusArea[role]?.container;

src/prefsModules/PrefsBoxOrderListBox.js

@@ -64,7 +64,7 @@ var PrefsBoxOrderListBox = GObject.registerClass({
      * `PrefsBoxOrderItemRows`) to settings.
      */
     saveBoxOrderToSettings() {
-        let currentBoxOrder = [ ];
+        let currentBoxOrder = [];
         for (let potentialPrefsBoxOrderItemRow of this) {
             // Only process PrefsBoxOrderItemRows.
             if (potentialPrefsBoxOrderItemRow.constructor.$gtype.name !== "PrefsBoxOrderItemRow") continue;