Debug assertion triggered on empty doctype

[Tpt]

Thank you for quick-xml and sorry for comming back with an other bug.

When parsing the file <!DoctyPE> using rusc "dev" profile the assertion "DocType must have a name" is triggered. In the "release" profile the assertion is not triggered and the parser returns an empty Event::Doctype()

Test failing in "dev" profile and passing in "release" profile:

#[test]
fn reproduce() {
    let data = b"<!DoctyPE>";
    let mut reader = Reader::from_reader(data.as_slice());
    let mut buf = Vec::new();
    loop {
        match reader.read_event_into(&mut buf) {
            Ok(Event::Eof) => break,
            Ok(Event::DocType(e)) => assert!(e.is_empty()), // assertion only executed in "release" mode
            _ => unreachable!()
        }
    }
}

[Mingun]

Yes, I think, we should either to parse this correctly into an event or return a normal error if this violates XML rules

[Tpt]

XML 1.0 grammar requires at least one "Name" into the Doctype declaration. So, this case seems to violate XML rules.