Fix doc build

Author: carver

eth/abc.py

@@ -374,7 +374,7 @@ def nonce(self) -> int:
     @abstractmethod
     def gas_price(self) -> int:
         """
-        Will raise :cls:`AttributeError` if get or set on a 1559 transaction.
+        Will raise :class:`AttributeError` if get or set on a 1559 transaction.
         """
         ...
 
@@ -3360,7 +3360,8 @@ def create_genesis_header(cls, **genesis_params: Any) -> BlockHeaderAPI:
         """
         Create a genesis header using this VM's rules.
 
-        This is currently equivalent to create_header_from_parent(None, **genesis_params)
+        This is equivalent to calling :meth:`create_header_from_parent`
+        with ``parent_header`` set to None.
         """
         ...