Flip `K` and `Q`

[al8n]

Hi @cuviper, in the indexmap-rs/indexmap#253 (comment), it was mentioned that flipping K and Q can avoid some annoying turbofish. The solution in the comment also applies to crossbeam-rs/crossbeam#1132.

Is it a good idea to apply the flipping to this crate now?

[cuviper]

Well it's a breaking change, and I wasn't certain if the flip would have other unforeseen effects, so I decided to leave it alone for now. Since crossbeam is using their own flipped copy of the traits, I suppose we can wait and see if experience reveals any new problems with that change.