### 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)

if (shader.is_null() && shader_inc.is_null()) {
		disk_changed->hide();
		return;
	}
	if (trim_trailing_whitespace_on_save) {
		trim_trailing_whitespace();
	}
	apply_shaders();
	Ref<Shader> edited_shader = shader_editor->get_edited_shader();
	if (edited_shader.is_valid()) {
		ResourceSaver::save(edited_shader);
	}
	if (shader.is_valid() && shader != edited_shader) {
		ResourceSaver::save(shader);
	}
	Ref<ShaderInclude> edited_shader_inc = shader_editor->get_edited_shader_include();
	if (edited_shader_inc.is_valid()) {
		ResourceSaver::save(edited_shader_inc);
	}
	if (shader_inc.is_valid() && shader_inc != edited_shader_inc) {
		ResourceSaver::save(shader_inc);
	}
	shader_editor->get_text_editor()->tag_saved_version();
	disk_changed->hide();
}
void TextShaderEditor::trim_trailing_whitespace() {