Fix some keyboard related stuff while we're here

Mark the primary menu as primary, so we get the F10 shortcut for free.
Also remove the Enter key shortcut from the BookCard's FlowBoxChild,
since it's no longer activatable, and instead the button inside it
responds to Return

cozy/ui/widgets/book_card.py

@@ -105,12 +105,8 @@ def _install_event_controllers(self):
         long_press_gesture = Gtk.GestureLongPress()
         long_press_gesture.connect("pressed", self._on_long_tap)
 
-        key_event_controller = Gtk.EventControllerKey()
-        key_event_controller.connect("key-pressed", self._on_key_press_event)
-
         self.add_controller(hover_controller)
         self.add_controller(long_press_gesture)
-        self.add_controller(key_event_controller)
 
     def set_playing(self, is_playing):
         self.play_button.set_playing(is_playing)
@@ -160,7 +156,3 @@ def _on_long_tap(self, gesture: Gtk.Gesture, *_):
         device = gesture.get_device()
         if device and device.get_source() == Gdk.InputSource.TOUCHSCREEN:
             self.menu_button.emit("activate")
-
-    def _on_key_press_event(self, controller, keyval, *_):
-        if keyval == Gdk.KEY_Return:
-            self.emit("open-book-overview", self.book)

data/ui/headerbar.blp

@@ -22,6 +22,7 @@ template $Headerbar: Box {
       tooltip-text: _("Options");
       menu-model: primary_menu;
       icon-name: 'open-menu-symbolic';
+      primary: true;
 
       accessibility {
         label: _("Open the options popover");