Improve aggregation docstrings to improve searchability

[SomeCoder23]

Closes #7378

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In generate_aggregations.py

• Add long_name parameter to Method class for searcher-friendly docstrings
• Update TEMPLATE_REDUCTION_SIGNATURE to use long_name instead of short method names
• Add long names: maximum, minimum, product, standard deviation, variance, cumulative sum, cumulative product
• Regenerate _aggregations.py files for xarray.core and xarray.namedarray"

I wrote the code, however Copilot was used to check if everything works fine and to generate the aggregation files from the generate_aggregations.py file

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@VeckoTheGecko

[VeckoTheGecko]

Hi @SomeCoder23 , thanks for the PR and the ping! It was great meeting you at the Scipy sprints :)

I have a lot of travel coming up so I may not be able to get around to reviewing this this week. If another maintainer is able have a look, go for it, otherwise I can have a look later around next weekend.

Actually, I'll try do this on airport internet :)

[VeckoTheGecko]

Hi @SomeCoder23 . Running the aggregation file creates the updated docstring, but it does so without the examples (hence the -1000 line diff here). Would you be able to follow the instructions in the Usage section of the script docstring to update all the docstring examples as well?

xarray/xarray/util/generate_aggregations.py

Lines 1 to 16 in aae7fef

	"""Generate module and stub file for arithmetic operators of various xarray classes.
	For internal xarray development use only.
	Usage:
	python xarray/util/generate_aggregations.py
	pytest --doctest-modules xarray/core/_aggregations.py --accept
	pytest --doctest-modules xarray/core/_aggregations.py
	pytest --doctest-modules xarray/namedarray/_aggregations.py --accept
	pytest --doctest-modules xarray/namedarray/_aggregations.py
	This requires [pytest-accept](https://github.com/max-sixty/pytest-accept).
	The second run of pytest is deliberate, since the first will return an error
	while replacing the doctests.
	"""

(make sure to do pixi shell before running the commands of course)

Then I can give it a proper review

[SomeCoder23]

Hey @VeckoTheGecko! I hope you are doing great! It was very nice meeting you as well :)
Thank you for checking my PR, I apologize for responding so late, I kinda got distracted after I created the pr and forgot to come back and check.
I ran all the commands in the usage section; sorry for not noticing them earlier.
Thank you!

[VeckoTheGecko]

All good! There's little expectation of timeliness or quick responses in open source anyway :) .

Thanks for pushing the edits. I realised in review that actually our aggregations are out of date! #11488 I think whoever last made edits forgot to re-run the aggregation generation.

I've put a couple pull requests up to deal with that. Once those are merged into main we can merge main into here and then I can give this a proper review without the other noise.