Update serde.rst

[Mr-Ruben]

As agreed here
#554
it would be helpful to mention some limitations/caveats.

I leave it to you how you want to express it.

Apologies if this is not the PR you were expecting. I don't know better.

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Changes

How I tested this

Notes

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.

[skrawcz]

@Mr-Ruben it doesn't appear that you added anything? It is the right file that was touched, but there's no actual content committed?

[Mr-Ruben]

Additionally ...

I have noticed Burr has good 'early errors detection' like "you are doing ... but you haven't done ..."

You may consider adding 2 more:

• If State has been / is being 'touched' by @serde.serialize.register(State) -> say something
• If the class passed on .with_typing(PydanticTypingSystem(ApplicationState)) has been 'touched' by @serde.serialize.register(cls) -> say something