Hello @RachelCho! I left a comment in your pull request, but I want to put the same information here in case anyone else has the same problem.
I believe the problem is the name of the file. Right now, it is:
That is so close, but it includes a space and a period at the end. In the same pull request, could you please try to edit the file and delete those last two characters of the title?
Good luck! If that doesn't fix it, let me know, and I'll do what I can to help.