Restore autoload for haskell-process-load-file

`haskell-process-load-file` lost its autoload directive during the
project reorganisation.

Author: Chris Barrett

haskell.el

@@ -264,6 +264,7 @@
       (display-buffer buffer)
       (other-window 1))))
 
+;;;###autoload
 (defun haskell-process-load-file ()
   "Load the current buffer file."
   (interactive)