Remove haskell-show.el

It requires the sexp-show package (which hasn't been updated since 2012
and was abandoned in 2014) to be installed from Hackage to work.
However, even if it's customization option is enabled it doesn't
actually seem to be used/called anywhere, making it less than useful.

Closes haskell#615

Author: ivan-m

Makefile

@@ -68,7 +68,6 @@ ELFILES = \
 	haskell-process.el \
 	haskell-repl.el \
 	haskell-session.el \
-	haskell-show.el \
 	haskell-simple-indent.el \
 	haskell-sort-imports.el \
 	haskell-string.el \

haskell-customize.el

@@ -274,12 +274,6 @@ ambiguous class constraint."
   :type 'boolean
   :group 'haskell-interactive)
 
-(defcustom haskell-interactive-mode-eval-pretty
-  nil
-  "Print eval results that can be parsed as Show instances prettily. Requires sexp-show (on Hackage)."
-  :type 'boolean
-  :group 'haskell-interactive)
-
 (defvar haskell-interactive-prompt "λ> "
   "The prompt to use.")
 

haskell-interactive-mode.el

@@ -32,7 +32,6 @@
 (require 'haskell-process)
 (require 'haskell-collapse)
 (require 'haskell-session)
-(require 'haskell-show)
 (require 'haskell-font-lock)
 (require 'haskell-presentation-mode)