move period inside quotations in compare branches (#35460)

Author: spudoodle

content/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-comparing-branches-in-pull-requests.md

@@ -71,7 +71,7 @@ For more information about Git commands to compare changes, see "[Git diff optio
 
 ## About three-dot comparison on {% data variables.product.prodname_dotcom %}
 
-Since the three-dot comparison compares with the merge base, it is focusing on "what a pull request introduces".
+Since the three-dot comparison compares with the merge base, it is focusing on "what a pull request introduces."
 
 When you use a two-dot comparison, the diff changes when the base branch is updated, even if you haven't made any changes to the topic branch. Additionally, a two-dot comparison focuses on the base branch. This means that anything you add is displayed as missing from the base branch, as if it was a deletion, and vice versa. As a result, the changes the topic branch introduces become ambiguous.