docs: remove references to non-existent packages

[jamesgeorge007]

What kind of change does this PR introduce?
Docs

Did you add tests for your changes?
N/A

If relevant, did you update the documentation?
Yup

Summary

• Remove references to the utils package, which was unioned to generators.
• Add a reference to the configtest package.

Does this PR introduce a breaking change?
Nope

Other information
N/A

[codecov]

Codecov Report

Merging #2395 (3911cd6) into master (7bd747a) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2395   +/-   ##
=======================================
  Coverage   71.27%   71.27%           
=======================================
  Files          46       46           
  Lines        2155     2155           
  Branches      568      568           
=======================================
  Hits         1536     1536           
  Misses        619      619           

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