cls.__module__ attribute might not be set #1071

>>> exec("""
... import msgspec
... S = msgspec.defstruct("S", [("x", int)])
... msgspec.convert({"x": 1}, type=S)
... """, {}, {})
Traceback (most recent call last):
  File "<python-input-8>", line 1, in <module>
    exec("""
    ~~~~^^^^
    import msgspec
    ^^^^^^^^^^^^^^
    S = msgspec.defstruct("S", [("x", int)])
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    msgspec.convert({"x": 1}, type=S)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    """, {}, {})
    ^^^^^^^^^^^^
  File "<string>", line 4, in <module>
  File "/Users/sobolev/Desktop/msgspec/src/msgspec/_utils.py", line 136, in get_class_annotations
    cls_globals = getattr(sys.modules.get(cls.__module__, None), "__dict__", {})
                                          ^^^^^^^^^^^^^^
AttributeError: __module__. Did you mean '.__reduce__' instead of '.__module__'?