Syntax errors are offset incorrectly when tabs are used

[KristianLyng]

I knew this going in, but I never fixed it/wrote an issue on it....

When calculate how far to indent when underlining syntax errors, we don't account for how some characters are wider than others. Most critical is tabs, which tend to be 8 character wide, but this can also include other none-1-char-wide-chars (e.g.: emojis).

Random test-case reveals this.

[KristianLyng]

Resolved with #62