docs: mention np.cumsum/np.cumprod on the relevant reference pages

[nickodell]

Issue with current documentation

Recently, while reviewing scipy/scipy#24198, the author of that PR said they were unable to find any cumulative sum function within the array API.

I was also unable to find this initially, because I was searching for the NumPy equivalent name, cumsum. Search link.

Idea or request for content

While it is understandable that the array API changes the name, it would be helpful if the pages for cumulative_sum and cumulative_prod mentions the equivalent NumPy function for people like me who don't know the new name of the function, so they can be found through search.

Example content for cumulative_sum:

Notes:

This function is similar to numpy.cumsum().

Example content for cumulative_prod:

Notes:

This function is similar to numpy.cumprod().

[kgryte]

For reference, NumPy also has cumulative_sum and cumulative_prod.

[lucascolley]

I would vote for just closing this, the See Also on https://numpy.org/doc/2.2/reference/generated/numpy.cumsum.html seems sufficient

[nickodell]

Fair enough. Like I said, I did eventually figure it out. IMO, it's not very obvious that you'd need to look at the NumPy docs to figure this out, but I can see that perspective.