Actually check that .error_position() is correct

Check position for zero actually does not check anything because this is start
position before parse. We move position by 1 by using Text event

failures (36):
    syntax::tag::unclosed3::ns_reader::async_tokio
    syntax::tag::unclosed3::ns_reader::borrowed
    syntax::tag::unclosed3::ns_reader::buffered
    syntax::tag::unclosed3::reader::async_tokio
    syntax::tag::unclosed3::reader::borrowed
    syntax::tag::unclosed3::reader::buffered
    syntax::tag::unclosed4::ns_reader::async_tokio
    syntax::tag::unclosed4::ns_reader::borrowed
    syntax::tag::unclosed4::ns_reader::buffered
    syntax::tag::unclosed4::reader::async_tokio
    syntax::tag::unclosed4::reader::borrowed
    syntax::tag::unclosed4::reader::buffered
    syntax::tag::unclosed5::ns_reader::async_tokio
    syntax::tag::unclosed5::ns_reader::borrowed
    syntax::tag::unclosed5::ns_reader::buffered
    syntax::tag::unclosed5::reader::async_tokio
    syntax::tag::unclosed5::reader::borrowed
    syntax::tag::unclosed5::reader::buffered
    syntax::tag::unclosed6::ns_reader::async_tokio
    syntax::tag::unclosed6::ns_reader::borrowed
    syntax::tag::unclosed6::ns_reader::buffered
    syntax::tag::unclosed6::reader::async_tokio
    syntax::tag::unclosed6::reader::borrowed
    syntax::tag::unclosed6::reader::buffered
    syntax::tag::unclosed7::ns_reader::async_tokio
    syntax::tag::unclosed7::ns_reader::borrowed
    syntax::tag::unclosed7::ns_reader::buffered
    syntax::tag::unclosed7::reader::async_tokio
    syntax::tag::unclosed7::reader::borrowed
    syntax::tag::unclosed7::reader::buffered
    syntax::tag::unclosed8::ns_reader::async_tokio
    syntax::tag::unclosed8::ns_reader::borrowed
    syntax::tag::unclosed8::ns_reader::buffered
    syntax::tag::unclosed8::reader::async_tokio
    syntax::tag::unclosed8::reader::borrowed
    syntax::tag::unclosed8::reader::buffered