refactor!(haskell): remove ghcide support

BREAKING CHANGE: ghcide was archived a while back and now primarily
exists as a library used in the development of haskell-language-server.
It is not recommended for end-users, only for development. To this end I
think including it in the module is more misleading than helpful, and
the people that really want to use it can easily set it up themselves.

Ref: https://github.com/haskell/ghcide/pull/939

modules/lang/haskell/config.el

@@ -47,6 +47,4 @@
 ;;; Backends
 
 (cond ((featurep! +dante)  (load! "+dante"))
-      ((or (featurep! +lsp)
-           (featurep! +ghcide))
-       (load! "+lsp")))
+      ((featurep! +lsp)    (load! "+lsp")))