Add small section about what happens to Gists if you change username.

content/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-personal-account-settings/changing-your-github-username.md

@@ -73,6 +73,10 @@ After changing your username, links to your previous profile page, such as `http
 
 {% ifversion fpt or ghec %}Git commits that were associated with your {% data variables.product.product_name %}-provided `noreply` email address won't be attributed to your new username and won't appear in your contributions graph.{% endif %} If your Git commits are associated with another email address you've [added to your GitHub account](/articles/adding-an-email-address-to-your-github-account), {% ifversion fpt or ghec %}including the ID-based {% data variables.product.product_name %}-provided `noreply` email address, {% endif %}they'll continue to be attributed to you and appear in your contributions graph after you've changed your username. For more information on setting your email address, see "[Setting your commit email address](/articles/setting-your-commit-email-address)."
 
+## Your gists
+
+After changing your username, the URLs to any public or secret gists will also change and previous links to these will return a 404 error. We recommend updating the links to these gists anywhere you may have shared them.
+
 ## Changing your username
 
 {% data reusables.user-settings.access_settings %}