These changes
1) 2cc36eb - "[jumbo] Add begin()/end() to Slice."
2) 578eeb7 - "Fix invalid pointer arithmetic in Hash (#1222)"
were committed in the public repository but never got imported to
the internal Google repository. Later, cl/713346733 landed in the
internal repo. When tooling published the internal change as
302786e ("Fix C++23 compilation errors in leveldb"), it
accidentally reverted commits (1) and (2).
This change re-commits a bundled version of (1) and (2) in the
public repo. This will then be imported to the private repo,
leaving the 2 in sync.