src/vs/editor/contrib/stickyScroll/browser/stickyScrollProvider.ts/StickyLineCandidateProvider/updateIndex
class StickyLineCandidateProvider:	private updateIndex(index: number) {
		if (index === -1) {
			index = 0;
		} else if (index < 0) {
			index = -index - 2;
		}
		return index;
	}