### 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)

flags &= ~(ShaderWarning::UNUSED_STRUCT);
			}
			if (flags & ShaderWarning::UNUSED_UNIFORM) {
				flags &= ~(ShaderWarning::UNUSED_UNIFORM);
			}
			if (flags & ShaderWarning::UNUSED_VARYING) {
				flags &= ~(ShaderWarning::UNUSED_VARYING);
			}
		}
		sl.set_warning_flags(flags);
		ShaderLanguage::ShaderCompileInfo comp_info;
		comp_info.global_shader_uniform_type_func = _get_global_shader_uniform_type;
		if (shader.is_null()) {
			comp_info.is_include = true;
		} else {
			Shader::Mode mode = shader->get_mode();
			comp_info.functions = ShaderTypes::get_singleton()->get_functions(RenderingServer::ShaderMode(mode));
			comp_info.render_modes = ShaderTypes::get_singleton()->get_modes(RenderingServer::ShaderMode(mode));
			comp_info.shader_types = ShaderTypes::get_singleton()->get_types();
		}
		code = code_pp;
		
		last_compile_result = sl.compile(code, comp_info);
		if (last_compile_result != OK) {
			String err_text;
			int err_line;
			Vector<ShaderLanguage::FilePosition> include_positions = sl.get_include_positions();
			if (include_positions.size() > 1) {
				
				err_line = include_positions[0].line;