Delete bus effect with Delete key

(cherry picked from commit 05656f2b29fbbaeac44346f5c2a67fb926c3e2c6)

editor/editor_audio_buses.cpp

@@ -563,6 +563,17 @@ void EditorAudioBus::_gui_input(const Ref<InputEvent> &p_event) {
 	}
 }
 
+void EditorAudioBus::_unhandled_key_input(Ref<InputEvent> p_event) {
+	Ref<InputEventKey> k = p_event;
+	if (k.is_valid() && k->is_pressed() && !k->is_echo() && k->get_scancode() == KEY_DELETE) {
+		TreeItem *current_effect = effects->get_selected();
+		if (current_effect && current_effect->get_metadata(0).get_type() == Variant::INT) {
+			_delete_effect_pressed(0);
+			accept_event();
+		}
+	}
+}
+
 void EditorAudioBus::_bus_popup_pressed(int p_option) {
 
 	if (p_option == 2) {
@@ -770,6 +781,7 @@ void EditorAudioBus::_bind_methods() {
 	ClassDB::bind_method("_effect_selected", &EditorAudioBus::_effect_selected);
 	ClassDB::bind_method("_effect_add", &EditorAudioBus::_effect_add);
 	ClassDB::bind_method("_gui_input", &EditorAudioBus::_gui_input);
+	ClassDB::bind_method("_unhandled_key_input", &EditorAudioBus::_unhandled_key_input);
 	ClassDB::bind_method("_bus_popup_pressed", &EditorAudioBus::_bus_popup_pressed);
 	ClassDB::bind_method("get_drag_data_fw", &EditorAudioBus::get_drag_data_fw);
 	ClassDB::bind_method("can_drop_data_fw", &EditorAudioBus::can_drop_data_fw);
@@ -797,6 +809,7 @@ EditorAudioBus::EditorAudioBus(EditorAudioBuses *p_buses, bool p_is_master) {
 	add_child(vb);
 
 	set_v_size_flags(SIZE_EXPAND_FILL);
+	set_process_unhandled_key_input(true);
 
 	track_name = memnew(LineEdit);
 	track_name->connect("text_entered", this, "_name_changed");

editor/editor_audio_buses.h

@@ -93,6 +93,7 @@ class EditorAudioBus : public PanelContainer {
 	mutable bool hovering_drop;
 
 	void _gui_input(const Ref<InputEvent> &p_event);
+	void _unhandled_key_input(Ref<InputEvent> p_event);
 	void _bus_popup_pressed(int p_option);
 
 	void _name_changed(const String &p_new_name);