This commit adds back "id" as the key within a script to specify a
stored script (which with file scripts now gone is no longer ambiguous).
It also adds "source" as a replacement for "code". This is in an attempt
to normalize how scripts are specified across both put stored scripts and script usages, including search template requests. This also deprecates the old inline/stored keys.
Add unit tests for `TopHitsAggregator` and convert some snippets in
docs for `top_hits` aggregation to `// CONSOLE`.
Relates to #22278
Relates to #18160
This change adds a special field named _none_ that allows to disable the retrieval of the stored fields in a search request or in a TopHitsAggregation.
To completely disable stored fields retrieval (including disabling metadata fields retrieval such as _id or _type) use _none_ like this:
````
POST _search
{
"stored_fields": "_none_"
}
````
Rename `fields` to `stored_fields` and add `docvalue_fields`
`stored_fields` parameter will no longer try to retrieve fields from the _source but will only return stored fields.
`fields` will throw an exception if the user uses it.
Add `docvalue_fields` as an adjunct to `fielddata_fields` which is deprecated. `docvalue_fields` will try to load the value from the docvalue and fallback to fielddata cache if docvalues are not enabled on that field.
Closes#18943
`stored_fields` parameter will no longer try to retrieve fields from the _source but will only return stored fields.
`fields` will throw an exception if the user uses it.
Add `docvalue_fields` as an adjunct to `fielddata_fields` which is deprecated. `docvalue_fields` will try to load the value from the docvalue and fallback to fielddata cache if docvalues are not enabled on that field.
Closes#18943
