Fix mismatch between docstring and code in robot_state.h

[JeroenDM]

Description

In robot_state.h, there was a mismatch between the docstring and the code. I updated the docstring to match the code.

I could also rename it to link_model, as in other parts of MoveIt. But I'm not sure this is necessary.

(I quickly tried to look for the reason of this change in git history but could not find it. But the why is not really relevant as long as the documentation and the code match I guess :) )

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[codecov]

Codecov Report

Merging #2215 into master will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2215      +/-   ##
==========================================
- Coverage   57.71%   57.68%   -0.03%     
==========================================
  Files         326      326              
  Lines       25663    25662       -1     
==========================================
- Hits        14811    14804       -7     
- Misses      10852    10858       +6     

Impacted Files	Coverage Δ
...bot_state/include/moveit/robot_state/robot_state.h	91.02% <ø> (ø)
...e/src/parameterization/model_based_state_space.cpp	70.34% <0.00%> (-2.76%)	⬇️
moveit_core/robot_model/src/joint_model_group.cpp	59.39% <0.00%> (-2.43%)	⬇️
...ipulation/pick_place/src/manipulation_pipeline.cpp	76.41% <0.00%> (-0.95%)	⬇️
..._core/collision_detection/src/collision_matrix.cpp	48.27% <0.00%> (-0.59%)	⬇️
...nning_scene_monitor/src/planning_scene_monitor.cpp	69.89% <0.00%> (-0.15%)	⬇️
...lude/moveit/collision_detection/collision_matrix.h	100.00% <0.00%> (ø)
...meterization/work_space/pose_model_state_space.cpp	82.99% <0.00%> (+0.68%)	⬆️
.../ompl_interface/src/detail/constrained_sampler.cpp	64.10% <0.00%> (+17.94%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d6666a9...be3eb0f. Read the comment docs.

[felixvd]

As far as I can see this has been part of a big batch commit by Ioan 7 years ago and looks like an oversight.

[rhaschke]

Thanks!