Adds note regarding memory requirement for rendering (#359)

# Description

Adds note regarding memory requirement for rendering as workflows
requiring rendering will need more VRAM available in the system.

## Type of change

- This change requires a documentation update

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## 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

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docs/source/setup/installation/index.rst

@@ -28,6 +28,7 @@ Local Installation
 .. note::
 
     We recommend system requirements with at least 32GB RAM and 16GB VRAM for Isaac Lab.
+    For workflows with rendering enabled, additional VRAM may be required.
     For the full list of system requirements for Isaac Sim, please refer to the
     `Isaac Sim system requirements <https://docs.isaacsim.omniverse.nvidia.com/latest/installation/requirements.html#system-requirements>`_.