src/vs/workbench/api/common/extHostTypes.ts/Range/isRange
class Range:	static isRange(thing: any): thing is vscode.Range {
		if (thing instanceof Range) {
			return true;
		}
		if (!thing) {
			return false;
		}
		return Position.isPosition((<Range>thing).start)
			&& Position.isPosition((<Range>thing.end));
	}