Missing `include_named_queries_score` in search and boolean query

[swallez]

include_named_queries_score is missing in the API spec, although it's present in the rest-spec.json files.

The comment in the rest-spec file doesn't match the explanation in the docs.

If this parameter really changes the shape of the result, we don't want to enable it for strongly-typed languages as it would lead to a more complex API (changing an array to a union of map and array) that would also be a breaking change.

Investigation needed as to what doc is right.