[docs] High-level REST client : incomplete docs

[olcbean]

In the high level REST client, a client specific response has been create for the get alias API that holds not only the aliases but also an error message, an exception and the status as part of the response.

For this API the rest client always returns a response ( even when an exception occurs, it is parsed and set in the response ). Should the docs be extended and clarify that the users should analyze the response in order to determine if an exception has occurred on the server or not?

Currently the docs refer only to the aliases :

elasticsearch/docs/java-rest/high-level/indices/get_alias.asciidoc

Lines 84 to 94 in c4f8df3

	[[java-rest-high-get-alias-response]]
	==== Get Alias Response
	The returned `GetAliasesResponse` allows to retrieve information about the
	executed operation as follows:
	["source","java",subs="attributes,callouts,macros"]
	--------------------------------------------------
	include-tagged::{doc-tests}/IndicesClientDocumentationIT.java[get-alias-response]
	--------------------------------------------------
	<1> Retrieves a map of indices and their aliases

elasticsearch/client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/IndicesClientDocumentationIT.java

Lines 1772 to 1774 in c4f8df3

	// tag::get-alias-response
	Map<String, Set<AliasMetaData>> aliases = response.getAliases(); // <1>
	// end::get-alias-response

---

#30536 : discusses the current get aliases API
#28799 : added the get aliases API to the high level REST client and introduced the client specific response

[elasticmachine]

Pinging @elastic/es-core-infra

[debadair]

[doc-issue-triage]