abbi* -> eqab*

[wlammen]

This is the final set of renamings from #4659 . When this PR is done, I will close it as well.

1. abbi2i -> eqabi
2. abbi1dv -> eqabcdv
3. abbi2dv -> eqabdv

This does not mean, we're ready. The next candidate is nabbi, that could be relabelled as nabbib, and have the sides flipped. Your opinions?

[icecream17]

As for nabbi, the change makes sense. Especially since the current-left hand side is somewhat arbitrary. suppvalbr is the only theorem that uses nabbi, and all that's needed is to change step 11 from 3bitr4i(6, 9, 10) to 3bitri(9, 6, 10c)

Edit: This makes the second example in https://github.com/metamath/set.mm/wiki/Minimizing#commutations outdated, but I will add the examples to my mathbox later (-> section "exemplar theorems", perhaps better renamed "illustrative theorems"). ralcom4 was obsoleted anyways.