### 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)

ERR_FAIL_COND(err_positions.size() == 0);
		String err_text = error_pp;
		int err_line = err_positions.front()->get().line;
		if (err_positions.size() == 1) {
			
			err_text = "error(" + itos(err_line) + "): " + err_text;
		} else {
			err_text = "error(" + itos(err_line) + ") in include " + err_positions.back()->get().file.get_file() + ":" + itos(err_positions.back()->get().line) + ": " + err_text;
			set_error_count(err_positions.size() - 1);
		}
		set_error(err_text);
		set_error_pos(err_line - 1, 0);
		for (int i = 0; i < get_text_editor()->get_line_count(); i++) {
			get_text_editor()->set_line_background_color(i, Color(0, 0, 0, 0));
		}
		get_text_editor()->set_line_background_color(err_line - 1, marked_line_color);
		set_warning_count(0);
	} else {
		ShaderLanguage sl;
		sl.enable_warning_checking(saved_warnings_enabled);
		uint32_t flags = saved_warning_flags;
		if (shader.is_null()) {
			if (flags & ShaderWarning::UNUSED_CONSTANT) {
				flags &= ~(ShaderWarning::UNUSED_CONSTANT);
			}
			if (flags & ShaderWarning::UNUSED_FUNCTION) {
				flags &= ~(ShaderWarning::UNUSED_FUNCTION);
			}
			if (flags & ShaderWarning::UNUSED_STRUCT) {