input: Mark virtual devices as such

This is for internal configuration purposes

include/sway/input/input-manager.h

@@ -14,6 +14,7 @@ struct sway_input_device {
 	struct wlr_input_device *wlr_device;
 	struct wl_list link;
 	struct wl_listener device_destroy;
+	bool is_virtual;
 };
 
 struct sway_input_manager {

sway/input/input-manager.c

@@ -374,6 +374,7 @@ void handle_virtual_keyboard(struct wl_listener *listener, void *data) {
 	}
 	device->data = input_device;
 
+	input_device->is_virtual = true;
 	input_device->wlr_device = device;
 	input_device->identifier = input_device_get_identifier(device);
 	wl_list_insert(&input_manager->devices, &input_device->link);
@@ -405,6 +406,7 @@ void handle_virtual_pointer(struct wl_listener *listener, void *data) {
 	}
 	device->data = input_device;
 
+	input_device->is_virtual = true;
 	input_device->wlr_device = device;
 	input_device->identifier = input_device_get_identifier(device);
 	wl_list_insert(&input_manager->devices, &input_device->link);