For ghc, it seemed that the conditional
```
if l:corrected_lines[-1] =~# ': error:$'
let l:line = substitute(l:line, '\v^\s+', ' ', '')
endif
```
was never being reached. It's actually better to unconditionally
collapse whitespace anyway and so I simply removed the conditional
check.
For hlint I added more information about the error. This changes the
reported error from `Error:` to something like:
` Error: Avoid lambda. Found: \ x -> foo x Why not: foo`
0ffef758ae