### 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)

return shader;
}
Ref<ShaderInclude> ShaderTextEditor::get_edited_shader_include() const {
	return shader_inc;
}
void ShaderTextEditor::set_edited_shader(const Ref<Shader> &p_shader) {
	set_edited_shader(p_shader, p_shader->get_code());
}
void ShaderTextEditor::set_edited_shader(const Ref<Shader> &p_shader, const String &p_code) {
	if (shader == p_shader) {
		return;
	}
	if (shader.is_valid()) {
		shader->disconnect(SNAME("changed"), callable_mp(this, &ShaderTextEditor::_shader_changed));
	}
	shader = p_shader;
	shader_inc = Ref<ShaderInclude>();
	set_edited_code(p_code);
	if (shader.is_valid()) {
		shader->connect(SNAME("changed"), callable_mp(this, &ShaderTextEditor::_shader_changed));
	}
}
void ShaderTextEditor::set_edited_shader_include(const Ref<ShaderInclude> &p_shader_inc) {