How to make the exclamation point symbol that's to the right of a file name, and is for that file, in the Xcode file tree go away?

Question

I have an exclamation point symbol that's to the right of a file name, and is for that file, in my Xcode file tree, and I'm trying to make it go away.

I've tried things like using git status to check the status of the repository, and I've tried git add -A, for staging, then committing, then pushing, and this still didn't work.

Also, the only thing that's different about this file compared to all of the other files in the project, is that the code in it is global in scope.

Is there any other way to make this exclamation point go away?