Nit: Remove pluralisation from names like finalizedBlocksHashes and prunedBlocksHashes

[jsdw]

finalizedBlocksHashes => finalizedBlockHashes
prunedBlocksHashes => prunedBlockHashes

I didn't spot whether there were other names with a similar pattern, but basically I'd recommend removing the middle "s" (assuming that we are talking about a list of hashes, one per block, and not a list of hashes where each represents multiple blocks (in which case blocksHashes feels ok to me))