refactor: remove sidebar-related code and update localization references

src/browser/components/preferences/zen-settings.js

@@ -919,16 +919,6 @@ var gZenCKSSettings = {
 };
 
 Preferences.addAll([
-  {
-    id: 'zen.sidebar.enabled',
-    type: 'bool',
-    default: true,
-  },
-  {
-    id: 'zen.sidebar.close-on-blur',
-    type: 'bool',
-    default: true,
-  },
   {
     id: 'zen.view.compact.hide-toolbar',
     type: 'bool',

src/browser/components/preferences/zenLooksAndFeel.inc.xhtml

@@ -134,27 +134,6 @@
       </vbox>
 </groupbox>
 
-<hbox id="zenSidePanelsCategory"
-      class="subcategory"
-      hidden="true"
-      data-category="paneZenLooks">
-<html:h1 data-l10n-id="pane-zen-side-panels-title"/>
-</hbox>
-
-<groupbox id="zenSidePanelsGroup" data-category="paneZenLooks" hidden="true" class="highlighting-group">
-      <label><html:h2 data-l10n-id="zen-side-panels-header"/></label>
-      <description class="description-deemphasized" data-l10n-id="zen-side-panels-description" />
-
-      <checkbox id="zenLooksAndFeelUseThemedToolbar"
-            data-l10n-id="zen-side-panels-enabled"
-            preference="zen.sidebar.enabled"/>
-      <hbox class="indent">
-            <checkbox id="zenLooksAndFeelSidebarCloseOnBlur"
-                  data-l10n-id="zen-side-panels-close-on-blur"
-                  preference="zen.sidebar.close-on-blur"/>
-      </hbox>
-</groupbox>
-
 <hbox id="zenGlanceCategory"
       class="subcategory"
       hidden="true"

src/browser/components/preferences/zenTabsManagement.inc.xhtml

@@ -6,7 +6,7 @@
 <html:h1 data-l10n-id="pane-workspaces-title"/>
 </hbox>
 
-<hbox id="zenSidePanelsCategory"
+<hbox id="zenTabManagementCategory"
       class="subcategory"
       hidden="true"
       data-category="paneZenTabManagement">