src/vs/editor/contrib/find/findDecorations.ts/FindDecorations/matchBeforePosition
class FindDecorations:	public matchBeforePosition(position: Position): Range | null {
		if (this._decorations.length === 0) {
			return null;
		}
		for (let i = this._decorations.length - 1; i >= 0; i--) {
			let decorationId = this._decorations[i];
			let r = this._editor.getModel().getDecorationRange(decorationId);
			if (!r || r.endLineNumber > position.lineNumber) {
				continue;
			}
			if (r.endLineNumber < position.lineNumber) {
				return r;
			}
			if (r.endColumn > position.column) {
				continue;
			}
			return r;
		}

		return this._editor.getModel().getDecorationRange(this._decorations[this._decorations.length - 1]);
	}