MAINT: fix assignment for sphinxdev (9.0) compatibility

[bsipocz]

This fixes some of the fixes for #214, thanks Adam!

I would say merge this if indeed there are fewer failues rather than waiting for the fix for problem 1

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.69%. Comparing base (208efd0) to head (dd9b3a0).
⚠️ Report is 24 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #215   +/-   ##
=======================================
  Coverage   89.69%   89.69%           
=======================================
  Files          31       31           
  Lines        1252     1252           
=======================================
  Hits         1123     1123           
  Misses        129      129           

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[bsipocz]

Changlelog failure is OK and preferred, this, along with any possibly others will get a "fix compatibility with sphinx ..." right before releasing.

[pllim]

Thank you! Yes, we can deal with the rest separately.

[pllim]

p.s. That was a milestone check, not a change log check.