Update RB examples in documentation

[vodovozovaliza]

This PR updates the examples for Standard Randomized Benchmarking in documentation.

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.

[codecov]

Codecov Report

Merging #330 (3c8e1eb) into main (4e329b3) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #330   +/-   ##
=======================================
  Coverage   36.57%   36.57%           
=======================================
  Files          44       44           
  Lines        3027     3027           
=======================================
  Hits         1107     1107           
  Misses       1920     1920           

Flag	Coverage Δ
unittests	36.57% <ø> (ø)

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[wilkensJ]

Thank you @vodovozovaliza !

[andrea-pasquale]

Thanks @vodovozovaliza.