src/vs/editor/contrib/inlineCompletions/ghostTextWidget.ts/registerDecorationType
function registerDecorationType(service: ICodeEditorService, description: string, keyPrefix: string, options: IDecorationRenderOptions) {
	const key = keyPrefix + (keyCounter++);
	service.registerDecorationType(description, key, options);
	return {
		dispose() {
			service.removeDecorationType(key);
		},
		resolve() {
			return service.resolveDecorationOptions(key, true);
		}
	};
}