feat(notify): add notify.threshold (#1693)

* feat: configurable notification level

add `notify.threshold` to setup opts

* feat: configurable notification level: add threshold example doc

* feat: configurable notification level: log always comes last

Co-authored-by: Alexander Courtis <alex@courtis.org>

lua/nvim-tree/log.lua

@@ -56,7 +56,7 @@ function M.setup(opts)
     if M.config.truncate then
       os.remove(M.path)
     end
-    require("nvim-tree.utils").notify.debug("nvim-tree.lua logging to " .. M.path)
+    require("nvim-tree.notify").debug("nvim-tree.lua logging to " .. M.path)
   end
 end