switch: Drop separate handling for US

The switches no longer use ON/OFF or o/|, so just use the
same class and artwork everywhere.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/496

data/gnome-shell-theme.gresource.xml

@@ -21,10 +21,8 @@
     <file>noise-texture.png</file>
     <file>pad-osd.css</file>
     <file>process-working.svg</file>
-    <file>toggle-off-us.svg</file>
     <file>toggle-off-intl.svg</file>
     <file>toggle-off-hc.svg</file>
-    <file>toggle-on-us.svg</file>
     <file>toggle-on-intl.svg</file>
     <file>toggle-on-hc.svg</file>
   </gresource>

data/theme/gnome-shell-sass/_common.scss

@@ -160,13 +160,8 @@ StScrollBar {
   width: 46px;
   height: 22px;
   background-size: contain;
-}
+  background-image: url("resource:///org/gnome/shell/theme/toggle-off-intl.svg");
-
+  &:checked { background-image: url("resource:///org/gnome/shell/theme/toggle-on-intl.svg"); }
-  @each $v in us, intl {
-    .toggle-switch-#{$v} {
-      background-image: url("resource:///org/gnome/shell/theme/toggle-off-#{$v}.svg");
-      &:checked { background-image: url("resource:///org/gnome/shell/theme/toggle-on-#{$v}.svg"); }
-    }
 }
 
 /* links */

data/theme/toggle-off-us.svg

@@ -1 +0,0 @@
-toggle-off-intl.svg

data/theme/toggle-on-us.svg

@@ -1 +0,0 @@
-toggle-on-intl.svg

js/ui/popupMenu.js

@@ -277,12 +277,6 @@ var Switch = class {
         this.actor = new St.Bin({ style_class: 'toggle-switch',
                                   accessible_role: Atk.Role.CHECK_BOX,
                                   can_focus: true });
-        // Translators: this MUST be either "toggle-switch-us"
-        // (for toggle switches containing the English words
-        // "ON" and "OFF") or "toggle-switch-intl" (for toggle
-        // switches containing "◯" and "|"). Other values will
-        // simply result in invisible toggle switches.
-        this.actor.add_style_class_name(_("toggle-switch-us"));
         this.setToggleState(state);
     }