Update content/manuals/engine/security/rootless/troubleshoot.md

Co-authored-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>

Author: AkihiroSuda

content/manuals/engine/security/rootless/troubleshoot.md

@@ -307,7 +307,8 @@ Use `docker run --net=host` to bypass the user-mode TCP/IP stack.
 This is applicable since Docker Engine v29.5.
 However, this requires the container to share the host network namespace, which may not be desirable for security reasons.
 
-**Workaround 2**
+##### Workaround 2: disable user-mode TCP/IP stack
+
 Alternatively, you can use the `lxc-user-nic` network driver (experimental) to disable the user-mode TCP/IP stack entirely.
 However, this requires configuring `/etc/lxc/lxc-usernet` for enabling the privileged helper.