appIcons/prefs: Follow upstream terminology for Favorite or Pinned apps

We use the same upstream wording here, to avoid having to change it in
multiple places, so it has to be dynamic. Depending on the version we're
running on.

Fixes micheleg#1697

Settings.ui

@@ -921,7 +921,7 @@
                                 <property name="can_focus">0</property>
                                 <property name="hexpand">1</property>
                                 <property name="halign">start</property>
-                                <property name="label" translatable="yes">Show favorite applications</property>
+                                <property name="label" translatable="yes">Show pinned applications</property>
 
                                 <layout>
                                   <property name="column">0</property>

appIcons.js

@@ -16,6 +16,8 @@ const Gettext = imports.gettext.domain('dashtodock');
 const __ = Gettext.gettext;
 const N__ = function(e) { return e };
 
+const Config = imports.misc.config;
+
 const AppDisplay = imports.ui.appDisplay;
 const AppFavorites = imports.ui.appFavorites;
 const BoxPointer = imports.ui.boxpointer;
@@ -1041,15 +1043,20 @@ const DockAppIconMenu = class DockAppIconMenu extends PopupMenu.PopupMenu {
                 this._appendSeparator();
 
                 let isFavorite = AppFavorites.getAppFavorites().isFavorite(this._source.app.get_id());
+                const [majorVersion] = Config.PACKAGE_VERSION.split('.');
 
                 if (isFavorite) {
-                    let item = this._appendMenuItem(_('Remove from Favorites'));
+                    const label = majorVersion >= 42 ? _('Unpin') :
+                        _('Remove from Favorites');
+                    let item = this._appendMenuItem(label);
                     item.connect('activate', () => {
                         let favs = AppFavorites.getAppFavorites();
                         favs.removeFavorite(this._source.app.get_id());
                     });
                 } else {
-                    let item = this._appendMenuItem(_('Add to Favorites'));
+                    const label = majorVersion >= 42 ? _('Pin to Dash') :
+                        _('Add to Favorites');
+                    let item = this._appendMenuItem(label);
                     item.connect('activate', () => {
                         let favs = AppFavorites.getAppFavorites();
                         favs.addFavorite(this._source.app.get_id());

prefs.js

@@ -224,6 +224,12 @@ var Settings = GObject.registerClass({
         this._icon_size_timeout = 0;
         this._opacity_timeout = 0;
 
+        if (Config.PACKAGE_VERSION.split('.')[0] < 42) {
+            // Remove this when we won't support earlier versions
+            this._builder.get_object('shrink_dash_label1').label =
+                __('Show favorite applications');
+        }
+
         this._monitorsConfig = new MonitorsConfig();
         this._bindSettings();
     }