src/vs/editor/common/viewModel/viewModelLines.ts/ViewModelLinesFromProjectedModel/_toValidViewLineNumber
class ViewModelLinesFromProjectedModel:	private _toValidViewLineNumber(viewLineNumber: number): number {
		if (viewLineNumber < 1) {
			return 1;
		}
		const viewLineCount = this.getViewLineCount();
		if (viewLineNumber > viewLineCount) {
			return viewLineCount;
		}
		return viewLineNumber | 0;
	}