In #574 I suggested that the sigils should be sorted in the ABNF. This is to track that comment.

currently we have:

reserved-annotation-start = "!" / "@" / "%" / "*" / "+"
                          / "<" / ">" / "?" / "~"

I would suggest this, which is in code point order:

reserved-annotation-start = "!" / "%" / "*" / "+"
                          / "<" / ">" / "?" / "@" / "~"

Also, are we missing these ASCII punctuation items: :, ;, (, ) ? (Note that & and ^ are private use sigils)