### 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)

int warning_count = 0;
	warnings_panel->push_table(2);
	for (int i = 0; i < warnings.size(); i++) {
		ShaderWarning &w = warnings[i];
		if (warning_count == 0) {
			if (saved_treat_warning_as_errors) {
				String error_text = "error(" + itos(w.get_line()) + "): " + w.get_message() + " " + TTR("Warnings should be fixed to prevent errors.");
				set_error_pos(w.get_line() - 1, 0);
				set_error(error_text);
				get_text_editor()->set_line_background_color(w.get_line() - 1, marked_line_color);
			}
		}
		warning_count++;
		int line = w.get_line();
		
		warnings_panel->push_cell();
		warnings_panel->push_color(warnings_panel->get_theme_color(SNAME("warning_color"), SNAME("Editor")));
		if (line != -1) {
			warnings_panel->push_meta(line - 1);
			warnings_panel->add_text(TTR("Line") + " " + itos(line));
			warnings_panel->add_text(" (" + w.get_name() + "):");
			warnings_panel->pop(); 
		} else {
			warnings_panel->add_text(w.get_name() + ":");
		}
		warnings_panel->pop(); 
		warnings_panel->pop();