Support serialization of NamedTuples by default

Hi! It would be cool to have it implemented. So far simplejson seems to be the only one that does it right (stdlib’s json serializes named tuples as list values, which is hardly a desired default behaviour):

>>> from simplejson import dumps
>>> from typing import NamedTuple
>>> class X(NamedTuple):
...     x: int
... 
>>> dumps(X(1))
'{"x": 1}'

[ijl]

Ok, if namedtuple becomes a simple type like a dict (in terms of one way of serializing it) that helps.

[belm0]

It’s unfortunate not to support a type that json handles. Because if I’m wrapping orjson for compatibility with json, this seems to be the only point to need an unknown-type handler. Moreover, if the caller of the wrapped dumps() is supplying a custom default= himself, then my wrapper must implement chaining with the NamedTuple handler…