func (p *parseState) autoLinkPlain(s string) []Inline {
	vd := &validDomainChecker{s: s}
	var out []Inline
Restart:
	for i := 0; i < len(s); i++ {
		c := s[i]
		if c == '@' {
			if before, link, after, ok := p.parseAutoEmail(s, i); ok {
				if before != "" {
					out = append(out, &Plain{Text: before})
				}
				out = append(out, link)
				vd.skip(len(s) - len(after))
				s = after
				goto Restart
			}
		}