docs: check_sphericity()

[DominiqueMakowski]

I was looking for the easystats wrapper for sphericity test for correlation matrices, stumbled on this, and then was like wait a second it doesn't work for correlation matrices. After digging up I remembered that it the other test is implemented in check_sphericity_bartlett, and not mentioned from each others docs. Should we unify this by merging the two tests generic functions? Or at least mention and document a bit better

[mattansb]

I don't think they should be merged - they have different purposes.

But perhaps we can link to one another right under of the title. Something along the lines "for Bartlett's test of sphericity see..."

[DominiqueMakowski]

I'll open a PR

[strengejacke]

bump

[DominiqueMakowski]

it has been merged no?

[strengejacke]

ah, ok. so why is this still open? :curious