Replaces standalone `SipHashUint256` with an `operator()` overload in `PresaltedSipHasher`.
Updates all hasher classes (`SaltedUint256Hasher`, `SaltedTxidHasher`, `SaltedWtxidHasher`) to use `PresaltedSipHasher` internally, enabling the same constant-state caching optimization while keeping behavior unchanged.
Benchmark was also adjusted to cache the salting part.
Historically, the headers have been bumped some time after a file has
been touched. Do it now to avoid having to touch them again in the
future for that reason.
-BEGIN VERIFY SCRIPT-
sed -i --regexp-extended 's;( 20[0-2][0-9])(-20[0-2][0-9])? The Bitcoin Core developers;\1-present The Bitcoin Core developers;g' $( git show --pretty="" --name-only HEAD~1 )
-END VERIFY SCRIPT-