Tackle the api schema changes/examples

Also add hlint ignore warning for ^. as we would need to provide
the type signature anyways (and it is a bit involved).

Author: v0d1ch

.hlint.yaml

@@ -1,2 +1,3 @@
 - ignore: {name: Redundant <$>, within: [Hydra.Contract.HeadTokens]}
 - ignore: {name: Redundant compare, within: [Hydra.PartySpec]}
+- ignore: {name: Redundant ^., within:[Hydra.Chain.Direct.TxSpec]}