[Editor] Add EditorPlugin::scene_saved signal

Matches the `EditorNode` one for parity with the exposed
`resource_saved` signal

doc/classes/EditorPlugin.xml

@@ -759,7 +759,7 @@
 		<signal name="resource_saved">
 			<param index="0" name="resource" type="Resource" />
 			<description>
-				Emitted when the given [param resource] was saved on disc.
+				Emitted when the given [param resource] was saved on disc. See also [signal scene_saved].
 			</description>
 		</signal>
 		<signal name="scene_changed">
@@ -771,7 +771,13 @@
 		<signal name="scene_closed">
 			<param index="0" name="filepath" type="String" />
 			<description>
-				Emitted when user closes a scene. The argument is file path to a closed scene.
+				Emitted when user closes a scene. The argument is a file path to the closed scene.
+			</description>
+		</signal>
+		<signal name="scene_saved">
+			<param index="0" name="filepath" type="String" />
+			<description>
+				Emitted when a scene was saved on disc. The argument is a file path to the saved scene. See also [signal resource_saved].
 			</description>
 		</signal>
 	</signals>

editor/editor_data.cpp

@@ -361,6 +361,12 @@ void EditorData::notify_resource_saved(const Ref<Resource> &p_resource) {
 	}
 }
 
+void EditorData::notify_scene_saved(const String &p_path) {
+	for (int i = 0; i < editor_plugins.size(); i++) {
+		editor_plugins[i]->notify_scene_saved(p_path);
+	}
+}
+
 void EditorData::clear_editor_states() {
 	for (int i = 0; i < editor_plugins.size(); i++) {
 		editor_plugins[i]->clear();

editor/editor_data.h

@@ -236,6 +236,7 @@ public:
 	Dictionary restore_edited_scene_state(EditorSelection *p_selection, EditorSelectionHistory *p_history);
 	void notify_edited_scene_changed();
 	void notify_resource_saved(const Ref<Resource> &p_resource);
+	void notify_scene_saved(const String &p_path);
 
 	bool script_class_is_parent(const String &p_class, const String &p_inherits);
 	StringName script_class_get_base(const String &p_class) const;

editor/editor_node.cpp

@@ -1805,6 +1805,7 @@ void EditorNode::_save_scene(String p_file, int idx) {
 
 	// This needs to be emitted before saving external resources.
 	emit_signal(SNAME("scene_saved"), p_file);
+	editor_data.notify_scene_saved(p_file);
 
 	_save_external_resources();
 	saving_scene = p_file; // Some editors may save scenes of built-in resources as external data, so avoid saving this scene again.

editor/editor_plugin.cpp

@@ -249,6 +249,10 @@ void EditorPlugin::notify_resource_saved(const Ref<Resource> &p_resource) {
 	emit_signal(SNAME("resource_saved"), p_resource);
 }
 
+void EditorPlugin::notify_scene_saved(const String &p_scene_filepath) {
+	emit_signal(SNAME("scene_saved"), p_scene_filepath);
+}
+
 bool EditorPlugin::forward_canvas_gui_input(const Ref<InputEvent> &p_event) {
 	bool success = false;
 	GDVIRTUAL_CALL(_forward_canvas_gui_input, p_event, success);
@@ -632,6 +636,7 @@ void EditorPlugin::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("scene_closed", PropertyInfo(Variant::STRING, "filepath")));
 	ADD_SIGNAL(MethodInfo("main_screen_changed", PropertyInfo(Variant::STRING, "screen_name")));
 	ADD_SIGNAL(MethodInfo("resource_saved", PropertyInfo(Variant::OBJECT, "resource", PROPERTY_HINT_RESOURCE_TYPE, "Resource")));
+	ADD_SIGNAL(MethodInfo("scene_saved", PropertyInfo(Variant::STRING, "filepath")));
 	ADD_SIGNAL(MethodInfo("project_settings_changed"));
 
 	BIND_ENUM_CONSTANT(CONTAINER_TOOLBAR);

editor/editor_plugin.h

@@ -160,6 +160,7 @@ public:
 	void notify_scene_changed(const Node *scn_root);
 	void notify_scene_closed(const String &scene_filepath);
 	void notify_resource_saved(const Ref<Resource> &p_resource);
+	void notify_scene_saved(const String &p_scene_filepath);
 
 	virtual bool forward_canvas_gui_input(const Ref<InputEvent> &p_event);
 	virtual void forward_canvas_draw_over_viewport(Control *p_overlay);