Add a small note in refinement docs for scala 3 users

[lenguyenthanh]

Because otherwise We'll have this error:

[error]    |No given instance of type smithy4s.RefinementProvider[fide.spec.PageFormat, String, fide.types.Natural] was found for parameter refinementProvider of method apply in class PartiallyAppliedRefinement.
[error]    |I found:
[error]    |
[error]    |    smithy4s.RefinementProvider.isomorphismConstraint[C, A, A0]
[error]    |
[error]    |But method isomorphismConstraint in trait LowPriorityImplicits does not match type smithy4s.RefinementProvider[fide.spec.PageFormat, String, fide.types.Natural].
[error]    |
[error]    |Note: given instance given_RefinementProvider_PageFormat_String_Natural in
[error]    |  object providers was not considered because it was not imported with `import given`.

PR Checklist (not all items are relevant to all PRs)

• Added unit-tests (for runtime code)
• Added bootstrapped code + smoke tests (when the rendering logic is modified)
• Added build-plugins integration tests (when reflection loading is required at codegen-time)
• Added alloy compliance tests (when simpleRestJson protocol behaviour is expanded/updated)
• Updated dynamic module to match generated-code behaviour
• Added documentation
• Updated changelog

[Baccata]

Thank you 👍