Merge bitcoin/bitcoin#36251: rest: add `generated` and `height` to spenttxouts JSON

1566a4767afd3865ee466d1aa2ce8237cb5c27c1 rest: add generated and height to spenttxouts JSON (0xb10c)

Pull request description:

  This adds the `generated` and `height` fields to the JSON REST endpoint `/rest/spenttxouts/BLOCKHASH.json` to match the prevout output of the getblock RPC with verbosity 3. The information for these fields is already available, but just was not exposed.

  The binary and hex formats aren't changed (here) to not break backwards compatibility with consumers of these endpoints. See the discussion in https://github.com/bitcoin/bitcoin/pull/32540#issuecomment-5665279713

ACKs for top commit:
  nervana21:
    tACK 1566a4767afd3865ee466d1aa2ce8237cb5c27c1
  willcl-ark:
    ACK 1566a4767afd3865ee466d1aa2ce8237cb5c27c1
  sedited:
    ACK 1566a4767afd3865ee466d1aa2ce8237cb5c27c1

Tree-SHA512: e0f57baa75d9b5e941fdf87179f293209af2fab16a151011a788b7f459d10ce50cf8b8ee2acc4d352e032aa5c76cf0a32dfb959c860938b988645844a2e75675