> Add missing includes and forward declarations, remove unused ones
> doc: Fix validation typo
> Remove txindex migration code
PR description:
> No supported version of Bitcoin used the legacy txindex, so all relevant nodes can be assumed to have upgraded. Thus, there is no need to keep this code any longer.
>
> As a temporary courtesy, provide a one-time warning on how to free the disk space used by the legacy txindex.
This is a backport of [[https://github.com/bitcoin/bitcoin/pull/22626 | core#22626]]
Depends on D12242