title: "[XCMP] Use the number of 'ready' pages in XCMP suspend logic"

doc:
  - audience: Runtime Dev
    description: |
      Semantics of the suspension logic in the XCMP queue pallet change from using the number of
      total pages to the number of 'ready' pages. The number of ready pages is now also exposed by
      the `MessageQueue` pallet to downstream via the queue `footprint`.

crates:
  - name: cumulus-pallet-xcmp-queue
    bump: patch
  - name: pallet-message-queue
    bump: patch
  - name: frame-support
    bump: major