Add default value to each one of the usages of `allow_no_indices`
since it differs between different APIs.
Relates to: #52534
(cherry picked from commit 2eb986488ac326d6da6ab8ad0203a94e08684a36)
Several files in the REST APIs nav section are included using
:leveloffset: tags. This increments headings (h2 -> h3, h3 -> h4, etc.)
in those files and removes the :leveloffset: tags.
Other supporting changes:
* Alphabetizes top-level REST API nav items.
* Change 'indices APIs' heading to 'index APIs.'
* Changes 'Snapshot lifecycle management' heading to sentence case.
* Made GET mappings consistent, supporting
* /{index}/_mappings/{type}
* /{index}/_mapping/{type}
* /_mapping/{type}
* Added "mappings" in the JSON response to align it with other responses
* Made GET warmers consistent, support /{index}/_warmers/{type} and /_warmer, /_warner/{name}
as well as wildcards and _all notation
* Made GET aliases consistent, support /{index}/_aliases/{name} and /_alias, /_aliases/{name}
as well as wildcards and _all notation
* Made GET settings consistent, added /{index}/_setting/{name}, /_settings/{name}
as well as supportings wildcards in settings name
* Returning empty JSON instead of a 404, if a specific warmer/
setting/alias/type is missing
* Added a ton of spec tests for all of the above
* Added a couple of more integration tests for several features
Relates #4071
The new internal get index settings api is more efficient when it comes to sending the index settings from the master to the client via the
Also the get index settings support now all the indices options.
Closes#4620
Lisa Cawley
Marios Trivyzas
James Rodewig
Zachary Tong
Clinton Gormley
Nik Everett
Alexander Reelsen
Martijn van Groningen