Improves docker X11 forwarding documentation (#685)

# Description

Clarify X11 forwarding configs in docs and warning messages.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

CONTRIBUTORS.md

@@ -54,6 +54,7 @@ Guidelines for modifications:
 * Vladimir Fokow
 * Zhengyu Zhang
 * Ziqi Fan
+* Johnson Sun
 
 ## Acknowledgements
 

docker/container.sh

@@ -224,9 +224,9 @@ x11_check() {
     else
         echo "[INFO] X11 Forwarding is configured as $__ISAACLAB_X11_FORWARDING_ENABLED in .container.yaml"
         if [ "$__ISAACLAB_X11_FORWARDING_ENABLED" = "1" ]; then
-            echo "[INFO] To disable X11 forwarding, set __ISAACLAB_X11_FORWARDING_ENABLED=0 in .container.yaml"
+            echo "[INFO] To disable X11 forwarding, set \`__ISAACLAB_X11_FORWARDING_ENABLED: 0\` in .container.yaml"
         else
-            echo "[INFO] To enable X11 forwarding, set __ISAACLAB_X11_FORWARDING_ENABLED=1 in .container.yaml"
+            echo "[INFO] To enable X11 forwarding, set \`__ISAACLAB_X11_FORWARDING_ENABLED: 1\` in .container.yaml"
         fi
     fi
 

docs/source/deployment/docker.rst

@@ -137,6 +137,17 @@ directories to the ``docker/artifacts`` directory. This is useful for copying th
     ./docker/container.sh stop
 
 
+X11 forwarding
+~~~~~~~~~~~~~~
+
+The container supports X11 forwarding, which allows the user to run GUI applications from the container and display them
+on the host machine.
+
+The first time a container is started with ``./docker/container.sh start``, the script prompts
+the user whether to activate X11 forwarding. This will create a file ``docker/.container.yaml`` to store the user's choice.
+Subsequently, X11 forwarding can be toggled by changing ``__ISAACLAB_X11_FORWARDING_ENABLED`` to 0 or 1 in ``docker/.container.yaml``.
+
+
 Python Interpreter
 ~~~~~~~~~~~~~~~~~~