Usually, once something is out on Github (or a public repo), there’s no way to make sure no one else has the bad commit.
If you simply want cleaner code history though, the way to do what you ask requires you to overwrite history both locally and on the remote project.
What you want is to either do a git commit --amend to modify your old commit if you’ve not already created a fresh commit with your changes.
If you’ve already created a fresh commit, you’ll want to use git rebase -i to squash your commit on top of the old one.
After you’ve made this change locally, and verified your commit looks the way you want it to, you’ll have to git push --force to overwrite history on the Github remote.
Here’s a tutorial on how to re-write history in git, it explains both the approaches listed in this answer.