src/vs/workbench/api/common/extHostWorkspace.ts/parseSearchInclude
function parseSearchInclude(include: RelativePattern | string | undefined): { includePattern?: string, folder?: URI } {
	let includePattern: string | undefined;
	let includeFolder: URI | undefined;
	if (include) {
		if (typeof include === 'string') {
			includePattern = include;
		} else {
			includePattern = include.pattern;
			includeFolder = include.baseFolder || URI.file(include.base);
		}
	}

	return {
		includePattern,
		folder: includeFolder
	};
}