Migration instructions from (add-hook 'haskell-mode-hook 'inf-haskell-mode)

Previous versions would allow me to connect to inferior-haskell-mode using hook
```
(add-hook 'haskell-mode-hook 'inf-haskell-mode)
```
(as an alternative to `'interactive-haskell-mode`). Now Emacs tells me:
```
File mode specification error: (void-function inf-haskell-mode)
```

This "inferior" mode had a simple interaction model, e.g. with `C-c C-l` load the current buffer into GHCi, displayed in the haskell buffer.

How can I set this up with the latest haskell-mode?

(I suggest to add such instructions to the user manual.)

Also, when I type `C-c C-l` I just get
```
haskell-mode-enable-process-minor-mode: Run ‘C-h f haskell-mode‘ for instruction how to setup a Haskell interaction mode.
```
However, the information given there are not very helpful. (See complaint at https://stackoverflow.com/questions/56501112/haskell-emacs-haskell-mode-run-c-h-f-haskell-mode-for-instruction-how-to-setu)

The issue points to the user manual and the `C-h f haskell-mode` help entry; start by comparing those instructions with the old `inf-haskell-mode` hook. Document the current setup for an inferior Haskell interaction and the expected `C-c C-l` workflow, then verify the instructions resolve the reported error.

Written by the indexing model from the issue text.