The comment in `readExecutionTransaction` is not actually relevant when
the `rlp.decode` template is called from a non-generic function.
The function still cannot be simply inlined; `is_valid_versioned_hashes`
is itself generic and would require an `export eth_types_rlp` to work
properly (generic sandwich issue). The non-generic function wrapper
seems simpler and avoids injecting RLP into importing modules.
73be2af0d9