Scala3 array - each / index

[OndrejSpanel]

Similar to #91, Scala 3 is missing support for Array (which is not a proper Seq).

I have implemented index, but each is a bit harder, as Array needs a ClassTag for construction.

[OndrejSpanel]

I have implemented each as well. To do so I had to simplify QuicklensFunctor.map, so that it always maps to the same type. It seems to me the Scala 2 version has the same limitation, therefore it should hopefully do no harm (and certainly the project still compiles and tests pass even with this more restrictive signature).

Knowing the element type stays the same, I am able to use Array.elemTag to provide the ClassTag needed for the array construction.

I am not absolutely sure if it would work properly on arrays of boxed primitive types - I am afraid casting Array.elemTag as ClassTag[A] is not really correct then.

Still I think it should be an improvement over the current version, which did not support Arrays at all.

[adamw]

Thanks :) indeed this seems to match scala 3 behavior