OCaml package documentation

1. dns 4.0.0
2. dns-certify 4.0.0
3. dns-cli 4.0.0
4. dns-client 4.0.0
5. dns-mirage 4.0.0
6. dns-resolver 4.0.0
7. dns-server 4.0.0
8. dns-tsig 4.0.0