Update contributing-to-a-project.md (#32781)

Co-authored-by: Anne-Marie <102995847+am-stead@users.noreply.github.com>

Author: EdwardLaird1

content/get-started/exploring-projects-on-github/contributing-to-a-project.md

@@ -33,6 +33,7 @@ This tutorial uses [the Spoon-Knife project](https://github.com/octocat/Spoon-Kn
 
    ![Screenshot of the main page of repository. A button, labeled with a fork icon and "Fork 59.3k," is outlined in dark orange.](/assets/images/help/repository/fork-button.png)
 1. Under "Owner," select the dropdown menu and click an owner for the forked repository.
+   >[!NOTE] If your username is grayed out, it's because the fork already exists. Instead, you should bring your existing fork up to date. For more information, see "[AUTOTITLE](/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork#syncing-a-fork-branch-from-the-web-ui)".
 1. By default, forks are named the same as their upstream repositories. Optionally, to further distinguish your fork, in the "Repository name" field, type a name.
 1. Optionally, in the "Description" field, type a description of your fork.
 1. Optionally, select **Copy the DEFAULT branch only**.