New asTypeFromValue function

[newhoggy]

Changelog

- description: |
    New `asTypeFromValue` function
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  # - breaking       # the API has changed in a breaking way
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Context

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Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[carbolymer]

This would be useful too:

Suggested change

	asType :: HasTypeProxy t => AsType t
	asType = proxyToAsType Proxy

[carbolymer]

don't you have to export it from Cardano.Api as well?