Documentation for method push-until-lazy

Documentation for method push-until-lazy, assembled from the following types:

role Iterator

From Iterator

(Iterator) method push-until-lazy

Defined as:

method push-until-lazy(Iterator:D: $target --> Mu)

Produces values until it considers itself to be lazy, and pushes them onto $target.

This matters mostly for iterators that have other iterators embedded, some of which might be lazy, while others aren't.