read_to_end breaks NsReader

[roblabla]

Heyo,

The NsReader::read_to_end seems to break its ability to resolve namespaces. This makes sense looking at its implementation: It simply delegates to the underlying readers' implementation, without updating its NamespaceResolver:

quick-xml/src/reader/ns_reader.rs

Lines 760 to 764 in 9fb797e

	pub fn read_to_end(&mut self, end: QName) -> Result<Span> {
	// According to the https://www.w3.org/TR/xml11/#dt-etag, end name should
	// match literally the start name. See `Self::check_end_names` documentation
	self.reader.read_to_end(end)
	}

Here's a reproducer:

    #[test]
    fn repro2() {
        const S: &'static str = r#"
<?xml version="1.0" encoding="UTF-8"?>
<oval_definitions xmlns="http://oval.mitre.org/XMLSchema/oval-definitions-5">

    <tests>
        <xmlfilecontent_test xmlns="http://oval.mitre.org/XMLSchema/oval-definitions-5#independent">
        </xmlfilecontent_test>
        <xmlfilecontent_test xmlns="http://oval.mitre.org/XMLSchema/oval-definitions-5#independent">
        </xmlfilecontent_test>
    </tests>
    <objects/>
</oval_definitions>"#;

        let mut reader = quick_xml::NsReader::from_str(S);
        let (ns, ev) = loop {
            let (ns, ev) = reader.read_resolved_event().unwrap();
            match ev {
                quick_xml::events::Event::Start(v) if v.local_name().as_ref() == b"xmlfilecontent_test" => {
                    reader.read_to_end(v.name()).unwrap();
                },
                quick_xml::events::Event::Empty(v) if v.local_name().as_ref() == b"objects" => break (ns, v),
                _ => (),
            }
        };
        assert_eq!(ns, quick_xml::name::ResolveResult::Bound(quick_xml::name::Namespace(b"http://oval.mitre.org/XMLSchema/oval-definitions-5")));
    }

[Mingun]

Yes, this is a bug, we should pop the namespace before the returning from the read_to_end() method.