Mark `haskell-process-do-{type,info}` autoloaded
Fix `C-u M-x haskell-process-do-type` inserting bad signature

For single-character identifiers or non-ascii identifiers,
`haskell-process-do-type` would put brackets around the
identifier, e.g. `(f) :: Int -> Int` instead of `f :: Int -> Int`.
This is fixed now.
Use `(next-error-internal)` instead of `(next-error 0)` error visiting

This is just a minor fix/optimization. `(next-error-internal)` better
matches the behavior of `compile-goto-error` in the presence of other
next-error capable because it avoids calling `next-error-find-buffer`.

This is related to #62