we don't need to check if the key is surrounded by quotation.
In fact, the key might not be strings if we register an extension to
customize the map key encoder/decoder.It may be an integer, float, or
even a struct.
* Map keys of custom types should serialize/deserialize using MarshalText/UnmarshalText when available
- this brings marshaling/unmarshaling behavior in line with encoding/json
- in general, any types that implement the interfaces from the encoding package (TextUnmarshaler, TextMarshaler, etc.) should use the provided method when available
When invalid types inside a map were marshalled (in general, as soon as
sorted maps have been configured), the error message has not been
propagated out of the map's `subStream`.
Also fix and re-enable the channel test, which now resembles the
behavior of `encoding/json` and tests both default and compatible
configurations.
Signed-off-by: Jens Erat <email@jenserat.de>
