feat(popup): add 'finalize_callback' option (#513)

Author: xactlyblue

lua/plenary/popup/init.lua

@@ -426,6 +426,10 @@ function popup.create(what, vim_options)
       { noremap = true }
     )
   end
+  
+  if vim_options.finalize_callback then
+    vim_options.finalize_callback(win_id, bufnr)
+  end
 
   -- TODO: Perhaps there's a way to return an object that looks like a window id,
   --    but actually has some extra metadata about it.