Docs: Add section about preventing tag creation matching branches

To avoid having tags with the same name as branches, this doc
update shows how we can use protected tags to prevent it.

doc/user/project/protected_tags.md

@@ -66,6 +66,26 @@ all matching tags:
 
 ![Protected tag matches](img/protected_tag_matches.png)
 
+## Prevent tag creation with the same name as branches
+
+A tag and a branch with identical names can contain different commits. If your
+tags and branches use the same names, users running `git checkout`
+commands might check out the _tag_ `qa` when they instead meant to check out
+the _branch_ `qa`.
+
+To prevent this problem:
+
+1. Identify the branch names you do not want used as tags.
+1. As described in [Configuring protected tags](#configuring-protected-tags),
+   create a protected tag:
+
+   - For the **Name**, provide a name, such as `stable`. You can also create a wildcard
+     like `stable-*` to match multiple names, like `stable-v1` and `stable-v2`.
+   - For **Allowed to Create**, select **No one**.
+   - Select **Protect**.
+
+Users can still create branches, but not tags, with the protected names.
+
 <!-- ## Troubleshooting
 
 Include any troubleshooting steps that you can foresee. If you know beforehand what issues