Allow pint.registry.Quantity to be used as a generic class

[zschaller27]

• Closes Typing in 0.26 #1770
• Executed pre-commit run --all-files or pixi run lint --all-files with no errors
• The change is fully covered by automated unit tests
• Documented in docs/ as appropriate
• Added an entry to the CHANGES file

[codspeed-hq]

CodSpeed Performance Report

Merging #2231 will not alter performance

_{Comparing zschaller27:master (71233b7) with master (5e5104d)}

Summary

✅ 448 untouched

[andrewgsavage]

Any idea why this doesn't work

ureg = UnitRegistry()
length = ureg.Quantity[int]

TypeError: <class 'pint.Quantity'> is not a generic class

[zschaller27]

Any idea why this doesn't work

ureg = UnitRegistry()
length = ureg.Quantity[int]

TypeError: <class 'pint.Quantity'> is not a generic class

I'd forgotten to change the UnitRegistry class signature to make use of the facets.MagnitudeT typevar. I've pushed that small change so this should work now.

[andrewgsavage]

nice one, thanks!