Enviroment.NewLine
should be correct. It should look like this:
return string.Format(
CultureInfo.InvariantCulture,
@"{0} {1} {2} {6}{{{6}{3} get{{ return {4}; }}{6}{5} set{{ {4} = value; }}{6} }}",
Accessibility.ForProperty(edmProperty),
propertyType,
_code.Escape(edmProperty),
_code.SpaceAfter(Accessibility.ForGetter(edmProperty)),
fieldName,
_code.SpaceAfter(Accessibility.ForSetter(edmProperty)),
Environment.NewLine);