### Godot version

Godot 4.0.3

### System information

Windows 10 64 bits NVIDIA GeForce GTX 1060

### Issue description

Ctrl+K is a shortcut normally used to comment out the current line. It works in the shader editor, but for some reason, it doesn't if your shader has the `.gdshaderinc` extension (aka it's a shader include). Shader Includes are the same language, we should be able to use that feature.

### Steps to reproduce

Create a `.gdshaderinc` file. Write some code in it. Observe you can't use Ctrl+K to comment out lines.

### Minimal reproduction project

[CommentLinesShaderInc.zip](https://github.com/godotengine/godot/files/11739881/CommentLinesShaderInc.zip)

goto_menu->set_switch_on_hover(true);
	goto_menu->get_popup()->connect("id_pressed", callable_mp(this, &TextShaderEditor::_menu_option));
	goto_menu->get_popup()->add_shortcut(ED_GET_SHORTCUT("script_text_editor/goto_line"), SEARCH_GOTO_LINE);
	goto_menu->get_popup()->add_separator();
	bookmarks_menu = memnew(PopupMenu);
	bookmarks_menu->set_name("Bookmarks");
	goto_menu->get_popup()->add_child(bookmarks_menu);
	goto_menu->get_popup()->add_submenu_item(TTR("Bookmarks"), "Bookmarks");
	_update_bookmark_list();
	bookmarks_menu->connect("about_to_popup", callable_mp(this, &TextShaderEditor::_update_bookmark_list));
	bookmarks_menu->connect("index_pressed", callable_mp(this, &TextShaderEditor::_bookmark_item_pressed));
	help_menu = memnew(MenuButton);
	help_menu->set_text(TTR("Help"));
	help_menu->set_switch_on_hover(true);
	help_menu->get_popup()->add_item(TTR("Online Docs"), HELP_DOCS);
	help_menu->get_popup()->connect("id_pressed", callable_mp(this, &TextShaderEditor::_menu_option));
	add_child(main_container);
	main_container->add_child(hbc);
	hbc->add_child(search_menu);
	hbc->add_child(edit_menu);
	hbc->add_child(goto_menu);
	hbc->add_child(help_menu);
	hbc->add_theme_style_override("panel", EditorNode::get_singleton()->get_gui_base()->get_theme_stylebox(SNAME("ScriptEditorPanel"), SNAME("EditorStyles")));
	VSplitContainer *editor_box = memnew(VSplitContainer);
	main_container->add_child(editor_box);
	editor_box->set_anchors_and_offsets_preset(Control::PRESET_FULL_RECT);
	editor_box->set_v_size_flags(SIZE_EXPAND_FILL);
	editor_box->add_child(shader_editor);
	FindReplaceBar *bar = memnew(FindReplaceBar);
	main_container->add_child(bar);