fix: align HexBytes32 hash with bytes (#258)

## Summary
Align HexBytes32 hashing with bytes to restore the hash/equality
contract for dict/set keys.

## Changes
- Use `bytes.__hash__` in `HexBytes32.__hash__`.
- Assert hash parity with `bytes(hb)` in
`test_hexbytes32_repr_hex_strip_hash`.

## Testing
- `./.venv/bin/python -m pytest`
- Compiled extension loaded:
`evmspec/_new.cpython-313-x86_64-linux-gnu.so`

## Risk and rollback
- Low risk: only hash value changes. Roll back by reverting this commit.

Author: BobTheBuidler

evmspec/data/_main.py

@@ -418,10 +418,6 @@ def __getitem__(self, key: SupportsIndex | slice) -> int | faster_hexbytes.HexBy
     # def __len__(self) -> Literal[32]:
     #    return 32
 
-    def __hash__(self) -> int:
-        # TODO: can we just remove this?
-        return hash(_hex(self))
-
     def hex(self) -> str:  # type: ignore [override]
         """
         Output hex-encoded bytes, with an "0x" prefix.

tests/data/test_main.py

@@ -77,7 +77,7 @@ def test_hexbytes32_repr_hex_strip_hash() -> None:
     assert repr(hb) == f"HexBytes32(0x{bytes.hex(hb)})"
     assert hb.hex() == f"0x{bytes.hex(hb)}"
     assert hb.strip() == "12"
-    assert hash(hb) == hash(bytes.hex(hb))
+    assert hash(hb) == hash(bytes(hb))
     zeroed = HexBytes32("0x" + "00" * 32)
     assert zeroed.strip() == "0"