=str #15026 take drop negative
=str #15026 add some scaladoc backticks
!str #15026 change thunk publisher api to () => Option[T]
Merge pull request #15760 from akka/wip-15026-jason-comments-patriknw

!str #15026 Fix issues pointed out by Jason
!str #15121 MaterializerSettings now uses a config object

Resolves #15121