Pretty-print comments preserved in RecordFields (#2021)

Also:
* Use tasty-silver for format tests
* Ignore annotations in isNormalizedIsConsistentWithNormalize

Author: sjakobi

dhall/dhall.cabal

@@ -678,6 +678,7 @@ Test-Suite tasty
         tasty-expected-failure                   < 0.13,
         tasty-hunit               >= 0.10     && < 0.11,
         tasty-quickcheck          >= 0.9.2    && < 0.11,
+        tasty-silver                             < 3.2 ,
         template-haskell                               ,
         text                      >= 0.11.1.0 && < 1.3 ,
         transformers                                   ,