Simplify "urged to avoid" -> "discouraged from".

Co-authored-by: Pierre-Antoine Champin <[email protected]>

index.html

@@ -3064,7 +3064,7 @@ <h3>Media Type Precision</h3>
         </ul>
 
         <p>
-Implementers are urged to avoid raising errors when it is possible to determine
+Implementers are discouraged from raising errors when it is possible to determine
 the intended media type from the payload, provided that the media type used is
 acceptable in the given protocol. For example, if an application only accepts
 payloads that conform to the rules associated with the `application/did` media