tui/input: defer nvim_paste properly.

Otherwise cursor and redraw code for normal and insert mode will not run. The
"tickle" workaround was used for this instead, and can now be removed.

The builtin vim.lua got the name
[string "-- Nvim-Lua stdlib: thevimmodule (:help l..."]
in error messages. Fix it to something reasonable.

src/nvim/api/vim.c

@@ -1283,8 +1283,6 @@ theend:
   api_free_array(args);
   if (cancel || phase == -1 || phase == 3) {  // End of paste-stream.
     draining = false;
-    // XXX: Tickle main loop to ensure cursor is updated.
-    loop_schedule_deferred(&main_loop, event_create(loop_dummy_event, 0));
   }
 
   return !cancel;