### 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)

Ref<InputEventKey> k = ev;
	if (k.is_valid() && k->is_pressed() && k->is_action("ui_menu", true)) {
		CodeEdit *tx = shader_editor->get_text_editor();
		tx->adjust_viewport_to_caret();
		_make_context_menu(tx->has_selection(), (get_global_transform().inverse() * tx->get_global_transform()).xform(tx->get_caret_draw_pos()));
		context_menu->grab_focus();
	}
}
void TextShaderEditor::_update_bookmark_list() {
	bookmarks_menu->clear();
	bookmarks_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/toggle_bookmark"), BOOKMARK_TOGGLE);
	bookmarks_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/remove_all_bookmarks"), BOOKMARK_REMOVE_ALL);
	bookmarks_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/goto_next_bookmark"), BOOKMARK_GOTO_NEXT);
	bookmarks_menu->add_shortcut(ED_GET_SHORTCUT("script_text_editor/goto_previous_bookmark"), BOOKMARK_GOTO_PREV);
	PackedInt32Array bookmark_list = shader_editor->get_text_editor()->get_bookmarked_lines();
	if (bookmark_list.size() == 0) {
		return;
	}
	bookmarks_menu->add_separator();
	for (int i = 0; i < bookmark_list.size(); i++) {
		String line = shader_editor->get_text_editor()->get_line(bookmark_list[i]).strip_edges();
		
		if (line.length() > 50) {
			line = line.substr(0, 50);
		}
		bookmarks_menu->add_item(String::num((int)bookmark_list[i] + 1) + " - \"" + line + "\"");
		bookmarks_menu->set_item_metadata(-1, bookmark_list[i]);
	}
}
void TextShaderEditor::_bookmark_item_pressed(int p_idx) {