src/vs/workbench/services/decorations/browser/decorationsService.ts/FileDecorationChangeEvent/merge
class FileDecorationChangeEvent:	static merge(all: (URI | URI[])[]): URI[] {
		let res: URI[] = [];
		for (let uriOrArray of all) {
			if (Array.isArray(uriOrArray)) {
				res = res.concat(uriOrArray);
			} else {
				res.push(uriOrArray);
			}
		}
		return res;
	}