Update how_to_use_git.md

documentation/how_to_use_git.md

@@ -172,7 +172,7 @@ Now you can make edits and commits as you normally would.
 
 It's good practice to update the remote repository with a copy of your branch.
 You should periodically push it once you have made some commits, and definitely
-once your are finished with the fix or feature associated with this branch.
+once you are finished with the fix or feature associated with this branch.
 ```
 git push origin name-of-my-branch
 ```