Revert "Require renderer once"

Causes circular requires after the previous commit.

This reverts commit 7413041.

Author: iusmac

lua/nvim-tree/diagnostics.lua

@@ -1,7 +1,6 @@
 local utils = require "nvim-tree.utils"
 local view = require "nvim-tree.view"
 local log = require "nvim-tree.log"
-local renderer = require "nvim-tree.renderer"
 
 local M = {}
 
@@ -129,7 +128,7 @@ function M.update()
     log.node("diagnostics", buffer_severity_dict, "update")
     log.profile_end(profile)
     if view.is_buf_valid(view.get_bufnr()) then
-      renderer.draw()
+      require("nvim-tree.renderer").draw()
     end
   end)
 end