[doc] New behavior of multiple use VERSION needs to be documented

[haarg]

Where
perlfunc

Description
The behavior of use VERSION needs to be updated to match the new behavior. This includes not allowing multiple use VERSION declarations with different versions, as well as builtin imports.

[jkeenan]

As of May 11 12:33 UTC, this is the only issue still bearing a Release Blocker label. (Of course, we should still be on the lookout for potential blockers.)

[book]

Fixed by #22235