Revert "nvim: after/ftplugin/cabal: Enable HLS on cabal files"

This reverts commit 34a5bbdacb.

HLS complains a lot (forgot the error) when trying to edit cabal files
making it almost unusable. It was nice to not require a separate plugin
for formatting cabal files, but, since this is not usable, disable it.

nvim/.config/nvim/after/ftplugin/cabal.lua

@@ -1,4 +0,0 @@
-local lsp_utils  = require('lsp-utils')
-local hls_config = lsp_utils.hls_config()
-
-vim.lsp.start(hls_config)

nvim/.config/nvim/lua/lsp-utils.lua

@@ -177,12 +177,7 @@ function M.hls_config()
     root_dir            = root_directory,
     filetypes           = { 'haskell' },
     single_file_support = true,
-    settings            = {
-      haskell = {
-        formattingProvider      = 'ormolu'  ,
-        cabalFormattingProvider = 'cabalfmt',
-      }
-    },
+    settings            = { haskell = { formattingProvider = 'ormolu' } },
   }
 end