Limited documentation on DNS variables and consistent use of variables

[JaneX8]

https://nuclei.projectdiscovery.io/templating-guide/protocols/dns/ does not document the use of the following variables
{{FQDN}}, {{RDN}}, {{DN}}, {{TLD}}, {{SD}} as defined here in v2/pkg/protocols/dns/dns.go:

Also I would probably recommend reusing the same naming schemes as much as possible. Meaning making {{RDN}} {{DN}} {{TLD}} et cetera available in HTTP requests too and probably renaming {{Host}} in HTTP to the DNS equivalent or visa versa.