Add line numbers to output

[asgrim]

I'd previously added line numbers to be displayed based on the line_from value. However, this is actually the line that the problem started on, rather than the line that the snippet started on. From my work so far, snippet_from is the only guidance to know what line we start on: however, the snippet_from is the character the snippet starts on, rather than the line. AFAIK the only way to figure out what line the snippet starts on would be to count \r or \n or \r\n between characters 0 and <snippet_from> ... :/ so not sure where to go here.