ci: include hugr-persistent in change detector

[acl-cqc]

https://github.com/CQCL/hugr/actions/runs/16067472898/job/45344608251 shows the check step not running, this should prevent that.

Driveby small change to a doc.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.03%. Comparing base (56906ce) to head (e27c17f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2417   +/-   ##
=======================================
  Coverage   82.03%   82.03%           
=======================================
  Files         245      245           
  Lines       45216    45216           
  Branches    40960    40960           
=======================================
  Hits        37095    37095           
  Misses       6108     6108           
  Partials     2013     2013           

Flag	Coverage Δ
python	85.36% <ø> (ø)
rust	81.69% <ø> (ø)

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