src/vs/editor/common/model/editStack.ts/getModelEOL
function getModelEOL(model: ITextModel): EndOfLineSequence {
	const eol = model.getEOL();
	if (eol === '\n') {
		return EndOfLineSequence.LF;
	} else {
		return EndOfLineSequence.CRLF;
	}
}