Merge pull request #51821 from Calinou/builtin-shaders-add-comments

Add comments at the top of each built-in shader to ease debugging

editor/plugins/animation_player_editor_plugin.cpp

@@ -1738,6 +1738,8 @@ AnimationPlayerEditor::AnimationPlayerEditor(EditorNode *p_editor, AnimationPlay
 
 	onion.capture.shader = Ref<Shader>(memnew(Shader));
 	onion.capture.shader->set_code(R"(
+// Animation editor onion skinning shader.
+
 shader_type canvas_item;
 
 uniform vec4 bkg_color;