For each API, the following updates were made:
- Add deprecation warnings to `Rest*Action`, plus tests in `Rest*ActionTests`.
- For each REST yml test, make sure there is one version without types, and another legacy version that retains types (called *_with_types.yml).
- Deprecate relevant methods on the Java HLRC requests/ responses.
- Update documentation (for both the REST API and Java HLRC).
This further applies the pattern set in #34125 to reduce copy-and-paste
in the single document CRUD portion of the High Level REST Client docs.
It also adds line wraps to snippets that are too wide to fit into the box
when rendered in the docs, following up on the work started in #34163.
Some features have been deprecated since `6.0` like the `_parent` field or the
ability to have multiple types per index. This allows to remove quite some
code, which in-turn will hopefully make it easier to proceed with the removal
of types.
Julie Tibshirani
Nik Everett
Adrien Grand
Luca Cavanna