message: Add reference to the set tag assignment
diff: @@ -469,7 +469,8 @@ impl<W: Write+Sized> Serializer<W> {
  self.write_type(Type::Tag, tag)
  }
  - /// write a tag that indicates that the following list is a finite set
  + /// Write a tag that indicates that the following list is a finite
  + /// set. See https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml.
  pub fn write_set_tag(self) -> Result<Self> {
  self.write_type(Type::Tag, 258)
  }
  