Checkboxes for common line delimiters?

[serin-delaunay]

Typing escape codes into the line delimiters box isn't very user-friendly when users might not know escape sequences like \n, and in any case they should be able to choose obvious options like that without needing to understand that kind of data.

A reasonable way to do that is with checkboxes. one each for newlines, full stops, question marks, exclamation marks, tabs, etc., and a text box for any additional characters.