Cleanup removed documentation for missing benchmarks

[dmathieu]

Which problem is this PR solving?

This resolved a bit of confusing documentation, stating that benchmarks need to be checked, when those don't exist anymore.

See:

• Removal of benchmarks: chore: split stable and experimental packages into groups using directories #2462
• chore: split stable and experimental packages into groups using directories #2462

Short description of the changes

Type of change

Please delete options that are not relevant.

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

How Has This Been Tested?

This is tested through the existing test suite.

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

Merging #2830 (406f0be) into main (c6dab2a) will not change coverage.
The diff coverage is n/a.

❗ Current head 406f0be differs from pull request most recent head 07816b7. Consider uploading reports for the commit 07816b7 to get more accurate results

@@           Coverage Diff           @@
##             main    #2830   +/-   ##
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  Coverage   93.46%   93.46%           
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  Files         163      163           
  Lines        5543     5543           
  Branches     1167     1167           
=======================================
  Hits         5181     5181           
  Misses        362      362           

[dyladan]

Thanks for cleaning this up