File gets removed from coverage wrongly when "// coverage:ignore-file" is used in Strings

[jtdLab]

File gets removed from coverage wrongly when "// coverage:ignore-file" is used in Strings

[liamappelbe]

At the moment we just split the file into lines and check if the line contains any of the ignore comments.

A full fix for this bug would involve parsing all the string literals, and only searching for the comments outside of the strings.

A quicker fix would be to switch from checking that the line contains the ignore comment to checking that it ends with it. We can't just check that the whole line matches (with optional white-space at the start), because it's common practice to put these lines at the end of a normal line of code.

This doesn't solve the problem for multi-line strings, where the comment could still appear on its own line, but hopefully that's an edge case on an edge case.

I'm also going to allow white-space after the comment, because otherwise there will be very tricky to debug errors:

// One of these is invalid:
// coverage:ignore-file
// coverage:ignore-file