With this regular expression I was able to match most difficult cases:

(?:[ \t]*Rem\s+|')(?![^"]*"(?:[^"]*"[^"]*")*[^"]*(?=[\r\n]+))[^\r\n]*

It only misses the lines of multiline comments after the first line (last two lines of my test code), but I think that we could get there too with some more work...