refactor: move mdx.nvim and neodim plugins to correct files for better organization

lua/plugins/editor.lua

@@ -1,6 +1,5 @@
 return {
 
-    -- Dimming the highlights of unused functions, variables, parameters, and more.
     {
         'zbirenbaum/neodim',
         enabled = false,
@@ -144,9 +143,4 @@ return {
             }
         end,
     },
-    {
-        'davidmh/mdx.nvim',
-        config = true,
-        dependencies = { 'nvim-treesitter/nvim-treesitter' },
-    },
 }