Correct '-dbcache' to '-prune' #29718

This looks like a typo, '-prune' is doubled not the '-dbcache' by my understanding.

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Conflicts

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• #29553 (assumeutxo: Add dumptxoutset height param, remove shell scripts by fjahr)

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ACK 416b9d9427c017fe7eb2975ca76f6a89ba24ab58

The minimum -dbcache value is 4 MiB, whereas the minimum -prune is 550 MiB.

In BlockManager::FindFilesToPrune there's this:

    const auto target = std::max(
        MIN_DISK_SPACE_FOR_BLOCK_FILES, GetPruneTarget() / chainman.GetAll().size());

During snapshot handling chainman.GetAll().size() is 2.

prune_target is set by -prune

MIN_DISK_SPACE_FOR_BLOCK_FILES is 550 MiB

This is line allocates half the -prune value to the background sync and half of it to the foreground sync, but never less than 550 MiB to each.

cc @jamesob / @fjahr

ACK 416b9d9427c017fe7eb2975ca76f6a89ba24ab58