Naming of some internal functions could be better

* [ ] `updateOrSnocWith[Key]`: Nothing in this name indicates that this function is for `Collision` handling! Could be named `insertCollisionWith[Key]#`.
* [ ] `updateOrConcatWithKey`: Same problem. How about `unionCollisionWithKey#`?!
* [ ] `updateWith#`: Same problem. `adjustCollision#`?!
* [ ] `clone`: Thaws an array of `maxChildren` elements. Let's just inline it into `update32M`.