Fix destination field in report delivery (#144)

It's mentioned twice; the correct value is `report`.

Closes #140

Author: dcreager

index.src.html

@@ -912,8 +912,6 @@ <h3 id="try-delivery" algorithm>
       ::  ""
       :   `destination`
       ::  "`report`"
-      :   `destination`
-      ::  ""
       :   `mode`
       ::  "`cors`"
       :   `unsafe-request` flag