2222c96dee test: Add notes on how to generate data/wallets/high_minversion (MarcoFalke)
Pull request description:
I forgot to do this in #16796
ACKs for top commit:
ryanofsky:
ACK 2222c96dee
Tree-SHA512: 5f24ffa641b97eac4febad42ade7228b14fa72335c918a10880c5dec86a3ecc3075a31526f275188e07fea95b8e2c6320c64f716099f604b00e13d5366fcee37