point to examples

Signed-off-by: qmuntal <[email protected]>

README.md

@@ -137,7 +137,7 @@ See [example_test.go](./example_test.go) for more examples.
 Untagged COSE_Sign1 messages can be signed and verified as above, using
 `cose.UntaggedSign1Message` instead of `cose.Sign1Message`.
 
-#### Signing and Verification of digested payloads
+#### Signing and Verification of payload digest
 
 When `cose.NewSigner` is used with PS{256,384,512} or ES{256,384,512}, the returned signer
 can be casted to the `cose.DigestSigner` interface, whose `SignDigest` method signs an
@@ -147,6 +147,8 @@ When `cose.NewVerifier` is used with PS{256,384,512} or ES{256,384,512}, the ret
 can be casted to the `cose.DigestVerifier` interface, whose `VerifyDigest` method verifies an
 already digested message.
 
+Please refer to [example_test.go](./example_test.go) for the API usage.
+
 ### About hashing
 
 `go-cose` does not import any hash package by its own to avoid linking unnecessary algorithms to the final binary.