contract_wrappers.py: fix misplaced doc

Previously, the routines `order_to_jsdict()` and `jsdict_to_order()`
were moved from contract_wrappers.exchange.types to
contract_wrappers.order_conversions.  However, the module-level
docstring describing those routines was accidentally left behind in
exchange.types.

python-packages/contract_wrappers/src/zero_ex/contract_wrappers/exchange/types.py

@@ -5,10 +5,6 @@
 containing hashes of the tuple's field names, because the name of a Solidity
 `struct`:code: isn't conveyed through the ABI.  This module provides type
 aliases with human-friendly names.
-
-Converting between the JSON wire format and the types accepted by Web3.py (eg
-`bytes` vs `str`) can be onerous.  This module provides conveniences for
-converting Exchange structs between JSON and Python objects.
 """
 
 from enum import auto, Enum

python-packages/contract_wrappers/src/zero_ex/contract_wrappers/order_conversions.py

@@ -1,4 +1,9 @@
-"""Utilities to convert between JSON and Python-native objects."""
+"""Utilities to convert between JSON and Python-native objects.
+
+Converting between the JSON wire format and the types accepted by Web3.py (eg
+`bytes` vs `str`) can be onerous.  This module provides conveniences for
+converting Exchange structs between JSON and Python objects.
+"""
 
 from copy import copy
 from typing import cast, Dict, Union