Update adding-an-existing-project-to-github-using-github-desktop.md

[Leo5233]

Why:

What's being changed:

Check off the following:

• I have reviewed my changes in staging. (look for the deploy-to-heroku link in your pull request, then click View deployment)
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[janiceilene]

This pull request is blank and appears have been opened accidentally. I'm going to close it now, but feel free to open a new issue or ask any questions in discussions!