* Remove SQL experimental banner and other doc adjustments.
Also,
- Adjust the ToC and other docs a bit so SQL and native queries are
presented on more equal footing.
- De-emphasize querying historicals and peons directly in the
native query docs. This is a really niche thing and may have been
confusing to include prominently in the very first paragraph.
- Remove DataSketches and Kafka indexing service from the experimental
features ToC. They are not experimental any longer and were there in
error.
* More notes.
* Slight tweak.
* Remove extra extra word.
* Remove RT node from ToC.
* o- Query Response format to be based on http 'accept' header & Query Payload contenty type to be based on 'content-type' header
* o- Query Response format to be based on http 'accept' header & Query Payload contenty type to be based on 'content-type' header
o- if Accept header is absent, it defaults to Content-Type header
* Feature: Query Response format to be based on http 'accept' header & Query Payload content type to be based on 'content-type' PR #4033
Minor change to a comment - restoring to previous wording
* Feature: Query Response format to be based on http 'accept' header & Query Payload content type to be based on 'content-type' PR #4033
o- minor change to check for empty string
Follow-up to #1773, which meant to add more useful query errors but
did not actually do so. Since that patch, any error other than
interrupt/cancel/timeout was reported as `{"error":"Unknown exception"}`.
With this patch, the error fields are:
- error, one of the specific strings "Query interrupted", "Query timeout",
"Query cancelled", or "Unknown exception" (same behavior as before).
- errorMessage, the message of the topmost non-QueryInterruptedException
in the causality chain.
- errorClass, the class of the topmost non-QueryInterruptedException
in the causality chain.
- host, the host that failed the query.