chore: clarify wording on ParseOptions

Clarify that `TimeStamp` and `NonceHasTimestamp` is used for checking clock-skew only.

parse.go

@@ -41,11 +41,11 @@ type ParseOptions struct {
  // The expected nonce if the authorization server has issued a nonce.
  Nonce string
 
- // Used to control if the `iat` field is used to control the proof age.
+ // Used to control if the `iat` field is within allowed clock-skew.
  // If set to true the authorization server has to validate the nonce timestamp itself.
  NonceHasTimestamp bool
 
- // The allowed age of the proof. Defaults to 1 minute if not specified.
+ // The allowed clock-skew on the `iat` of the proof. Defaults to 1 minute if not specified.
  TimeWindow *time.Duration
 
  // dpop_jkt parameter that is optionally sent by the client to the authorization server on token request.