Adds warning for correct annotation method (#472)

# Description

<!--
Thank you for your interest in sending a pull request. Please make sure
to check the contribution guidelines.

Link:
https://isaac-sim.github.io/IsaacLab/main/source/refs/contributing.html
-->

Per SQA feedback, adding a warning in Mimic docs to tell users that
subtask annotation indices must be unique.

## Type of change

<!-- As you go through the list, delete the ones that are not
applicable. -->

- Documentation update


## 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
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

<!--
As you go through the checklist above, you can mark something as done by
putting an x character in it

For example,
- [x] I have done this task
- [ ] I have not done this task
-->

docs/source/overview/teleop_imitation.rst

@@ -546,6 +546,11 @@ generated using Isaac Lab Mimic for the ``Isaac-NutPour-GR1T2-Pink-IK-Abs-Mimic-
       --input_file ./datasets/dataset_gr1_nut_pouring.hdf5 \
       --output_file ./datasets/dataset_annotated_gr1_nut_pouring.hdf5 --enable_pinocchio
 
+   .. warning::
+      There are multiple right eef annotations for this task. Annotations for subtasks for the same eef cannot have the same action index.
+      Make sure to annotate the right eef subtasks with different action indices.
+
+
    To generate the dataset:
 
    .. code:: bash