feat(explorer): add filesystem watchers (#1304)

* feat(explorer): add experimental watchers

This commit introduces watchers to update the tree.
This behavior is introduced behind an "filesystem_watchers" option
which should prevent instabilities.
It will become the default at some point.

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

lua/nvim-tree/actions/rename-file.lua

@@ -37,9 +37,15 @@ function M.fn(with_sub)
       a.nvim_out_write(node.absolute_path .. " ➜ " .. new_file_path .. "\n")
       utils.rename_loaded_buffers(node.absolute_path, new_file_path)
       events._dispatch_node_renamed(abs_path, new_file_path)
-      require("nvim-tree.actions.reloaders").reload_explorer()
+      if M.enable_reload then
+        require("nvim-tree.actions.reloaders").reload_explorer()
+      end
     end)
   end
 end
 
+function M.setup(opts)
+  M.enable_reload = not opts.filesystem_watchers.enable
+end
+
 return M