src/vs/editor/contrib/find/findModel.ts/FindModelBoundToEditorModel/_prevSearchPosition
class FindModelBoundToEditorModel:	private _prevSearchPosition(before: Position) {
		let isUsingLineStops = this._state.isRegex && (
			this._state.searchString.indexOf('^') >= 0
			|| this._state.searchString.indexOf('$') >= 0
		);
		let { lineNumber, column } = before;
		let model = this._editor.getModel();

		if (isUsingLineStops || column === 1) {
			if (lineNumber === 1) {
				lineNumber = model.getLineCount();
			} else {
				lineNumber--;
			}
			column = model.getLineMaxColumn(lineNumber);
		} else {
			column--;
		}

		return new Position(lineNumber, column);
	}