Type constraint changes

Say there are two classes:

```
class A a where
...

class A a => B a where
...
```

Assuming that the behaviour of `f` doesn't change, are any of these type changes permissible for a minor version bump?

1. Constraint relaxation

```diff
-f :: B a => a -> X
+f :: A a => a -> X
```

2. Removing a redundant constraint

```diff
-f :: (A a, B a) => a -> X
+f :: B a => a -> X
```

Start by reading issue #65 and its existing discussion, then compare both proposed type-signature changes with the repository's Haskell Package Version Policy. Done means reaching a settled policy conclusion for each case and recording that clarification in the specification.

Written by the indexing model from the issue text.