Adding a `Data.evolve()` function for updating data structures

interface Person extends Data.Case {
   name: string;
   age: number;
}

pipe(
    // ... Some person ...
   Struct.evolve({ age: add1 }),
   // ... Now they're a year older
   // but I've lost the Equals and Hash methods
   Data.struct, // get back the Equals and Hash
)