Scala 3 specific stdlib improvements

[bishabosha]

@OndrejSpanel

Interesting, thanks. I can see assert there, but not locally or implicitly, only summon.

Oh that is interesting, I think before 3.0.0 this was the case, but we did some “cleanup” which probably decided it was not worth patching those methods - but at least assert exists in the 2.13 Predef also