Improve `adapt_precision` and `restructure`

[emmt]

As discussed with @FerreolS, proposed improvements:

1. adapt_precision should only change objects that have floating-point values (e.g., in tuples), i.e. not integers.

2. By default, adapt_precision should be applicable to any structure using destructure and restructure and with the above heuristic. This could be done for instances and types as well.

Introspection (and @generated) can be used for that: the parameters of a type T are given by T.parameters while T.types yields the types of the fields.