Cardano Updates

Signed-off-by: William Hankins <[email protected]>

Signed-off-by: Aurora Gaffney <[email protected]>

This field is optional according to the CDDL.

Remove unused import

Signed-off-by: Chris Gianelloni <[email protected]>

Signed-off-by: Chris Gianelloni <[email protected]>

The `Show` instance for Mismatch was modified to show type level information.
The same thing needs to be done for the `TreeDiff` instance.

Example of the `Expr`:

```
ghci> toExpr (Mismatch @RelEQ (42 :: Int) 100)
Rec "Mismatch (RelEQ)" (fromList [("supplied",App "42" []),("expected",App "100" [])])
```

also complain when the exact rollback point is not found, instead of
silently moving to a different point's state

also complain when trying to roll back to a point before the tip

Signed-off-by: Roland Kuhn <[email protected]>

since the check for missing/redundant script witnesses will be done at
top level

since the fixup is not implemented, and they correctly fail the checks
in rules