### 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<Shader> rel_shader = ResourceLoader::load(shader->get_path(), shader->get_class(), ResourceFormatLoader::CACHE_MODE_IGNORE);
	ERR_FAIL_COND(!rel_shader.is_valid());
	shader_editor->set_block_shader_changed(true);
	shader->set_code(rel_shader->get_code());
	shader_editor->set_block_shader_changed(false);
	shader->set_last_modified_time(rel_shader->get_last_modified_time());
	shader_editor->reload_text();
}
void TextShaderEditor::_reload_shader_include_from_disk() {
	Ref<ShaderInclude> rel_shader_include = ResourceLoader::load(shader_inc->get_path(), shader_inc->get_class(), ResourceFormatLoader::CACHE_MODE_IGNORE);
	ERR_FAIL_COND(!rel_shader_include.is_valid());
	shader_editor->set_block_shader_changed(true);
	shader_inc->set_code(rel_shader_include->get_code());
	shader_editor->set_block_shader_changed(false);
	shader_inc->set_last_modified_time(rel_shader_include->get_last_modified_time());
	shader_editor->reload_text();
}
void TextShaderEditor::_reload() {