Fix parsing of units string with same canonalized name

[jules-ch]

• Closes Unit object gives wrong unit when mixing aliases #1441& Quantity __new__ not parsing units string properly if some metric terms are abbreviated and some are not #1142
• Executed pre-commit run --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

[keewis]

looks good to me

[keewis]

as far as I can tell (I don't really use type hints myself), in newer versions of python, type hints with = None imply Optional:

Suggested change

	case_sensitive: Optional[bool] = None,
	case_sensitive: bool = None,

[jules-ch]

Mypy support implicit Optional but explicit is prefered.

https://stackoverflow.com/questions/62732402/can-i-omit-optional-if-i-set-default-to-none

[hgrecco]

Looks good to me!

[jules-ch]

Thanks for the quick review !