Issue 1249 which key comments (nvim-lua#1263)

* Tweak outdated comment about lazy's `config` key usage.

Remove outdated comment describing use of `config` key, replacing with
corrected `opt` key note.

Fixes nvim-lua#1249

* fix typo opt -> opts

Fixes nvim-lua#1250

Author: benfleis

init.lua

@@ -267,7 +267,7 @@ require('lazy').setup({
   -- which loads which-key before all the UI elements are loaded. Events can be
   -- normal autocommands events (`:help autocmd-events`).
   --
-  -- Then, because we use the `opt` key (recommended), the configuration runs
+  -- Then, because we use the `opts` key (recommended), the configuration runs
   -- after the plugin has been loaded as `require(MODULE).setup(opts)`.
 
   { -- Useful plugin to show you pending keybinds.