Fix broken link SciTools/iris#6427

[trexfeathers]

🚀 Pull Request

Description

Closes #6427

@pp-mo you've made the link-check process so much less painful. Chapeau 🎩

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.80%. Comparing base (90e36fe) to head (4213ab3).
⚠️ Report is 101 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6429   +/-   ##
=======================================
  Coverage   89.80%   89.80%           
=======================================
  Files          90       90           
  Lines       23752    23752           
  Branches     4418     4418           
=======================================
  Hits        21331    21331           
  Misses       1672     1672           
  Partials      749      749           

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[trexfeathers]

Thanks @rcomer!