Describe the bug

#23276 added keyboard shortcuts to move the blocks. Nice improvement for all keyboard users. Pending #3218.

However, screen reader users don't get any confirmation of the move action. The only chance they have to check a block has been moved to the intended position is to explore the content around the block and verify it in a tedious, laborious, process.

It would be great to add a couple simple audible speak() messages to confirm the result of the move actions.

ideally the messages should also announce the new position. For example:

• "Block moved up to position {n}"
• "Block moved down to position {n}"