Rename KeyBindingMode to ActionMode

The keybinding mode is no longer used exclusively for actions triggered
by keybindings, so reflect this by a more generic name.

https://bugzilla.gnome.org/show_bug.cgi?id=740237

js/ui/panel.js

@@ -893,7 +893,7 @@ const Panel = new Lang.Class({
 
         this.statusArea = {};
 
-        this.menuManager = new PopupMenu.PopupMenuManager(this, { keybindingMode: Shell.KeyBindingMode.TOPBAR_POPUP });
+        this.menuManager = new PopupMenu.PopupMenuManager(this, { actionMode: Shell.ActionMode.TOPBAR_POPUP });
 
         this._leftBox = new St.BoxLayout({ name: 'panelLeft' });
         this.actor.add_actor(this._leftBox);