Feature: Generate AsyncAPI from msgspec.Struct

[dolfinus]

To suggest an idea or inquire about a new Message Broker supporting feature or any other enhancement, please follow this template:

Is your feature request related to a problem? Please describe.

Since 0.6, FastStream is going to support MsgSpec (according to https://github.com/Lancetnik/FastDepends/blob/51524261c847998bb3dafe7fc8dff76c23321396/fast_depends/msgspec/serializer.py). But for now, AsyncAPI is build only for Pydantic models, although MsgSpec also supports generating JSON Schema for specific model.

It would be nice if FastStream could generate AsyncAPI for MsgSpec structs.

Describe the solution you'd like

Feature code example

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Additional context

[Lancetnik]

For sure, It is in roadmap