Clarify DNS query record type / class type source data

The use of query record type / class type may not be clear. DNS requests will include a record type, but the answers will also include a record type - the answers may include other record types than what was requested, such as a CNAME response.

Clarify that the record request type should prefer the request record/class type where the log source provides the query record/class types, but that if absent the response record/class types can be used.

Locate the documentation describing DNS query record and class types, then read how request and response fields are currently explained. Clarify that request values are preferred when available and response values are a fallback, including that responses may contain types such as CNAME; update the relevant HTML documentation and verify the wording is consistent.

Written by the indexing model from the issue text.