SLM Start/Stop HLRC and docs (#47966)

This commit adds HLRC support and documentation for the SLM Start and
Stop APIs, as well as updating existing documentation where appropriate.

This commit also ensures that the SLM APIs are properly included in the
HLRC documentation.

docs/java-rest/high-level/ilm/snapshot_lifecycle_management_status.asciidoc

@@ -0,0 +1,36 @@
+--
+:api: slm-status
+:request: SnapshotLifecycleManagementStatusRequest
+:response: AcknowledgedResponse
+--
+[role="xpack"]
+[id="{upid}-{api}"]
+=== Snapshot Lifecycle Management Status API
+
+
+[id="{upid}-{api}-request"]
+==== Request
+
+The Snapshot Lifecycle Management Status API allows you to retrieve the status
+of Snapshot Lifecycle Management
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-request]
+--------------------------------------------------
+
+
+[id="{upid}-{api}-response"]
+==== Response
+
+The returned +{response}+ indicates the status of Snapshot Lifecycle Management.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-response]
+--------------------------------------------------
+<1> The returned status can be `RUNNING`, `STOPPING`, or `STOPPED`.
+
+include::../execution.asciidoc[]
+
+

docs/java-rest/high-level/ilm/start_snapshot_lifecycle_management.asciidoc

@@ -0,0 +1,36 @@
+--
+:api: slm-start-slm
+:request: StartSLMRequest
+:response: AcknowledgedResponse
+--
+[role="xpack"]
+[id="{upid}-{api}"]
+=== Start Snapshot Lifecycle Management API
+
+
+[id="{upid}-{api}-request"]
+==== Request
+
+The Start Snapshot Lifecycle Management API allows you to start Snapshot
+Lifecycle Management if it has previously been stopped.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-request]
+--------------------------------------------------
+
+
+[id="{upid}-{api}-response"]
+==== Response
+
+The returned +{response}+ indicates if the request to start Snapshot Lifecycle
+Management was received.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-response]
+--------------------------------------------------
+<1> Whether or not the request to start Snapshot Lifecycle Management was
+acknowledged.
+
+include::../execution.asciidoc[]

docs/java-rest/high-level/ilm/stop_snapshot_lifecycle_management.asciidoc

@@ -0,0 +1,38 @@
+--
+:api: slm-stop-slm
+:request: StopSLMRequest
+:response: AcknowledgedResponse
+--
+[role="xpack"]
+[id="{upid}-{api}"]
+=== Stop Snapshot Lifecycle Management API
+
+
+[id="{upid}-{api}-request"]
+==== Request
+
+The Stop Snapshot Management API allows you to stop Snapshot Lifecycle
+Management temporarily.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-request]
+--------------------------------------------------
+
+
+[id="{upid}-{api}-response"]
+==== Response
+
+The returned +{response}+ indicates if the request to stop Snapshot
+Lifecycle Management was received.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests-file}[{api}-response]
+--------------------------------------------------
+<1> Whether or not the request to stop Snapshot Lifecycle Management was
+acknowledged.
+
+include::../execution.asciidoc[]
+
+

docs/java-rest/high-level/supported-apis.asciidoc

@@ -579,6 +579,35 @@ include::ilm/lifecycle_management_status.asciidoc[]
 include::ilm/retry_lifecycle_policy.asciidoc[]
 include::ilm/remove_lifecycle_policy_from_index.asciidoc[]
 
+[role="xpack"]
+== Snapshot Lifecycle Management APIs
+
+:upid: {mainid}-ilm
+:doc-tests-file: {doc-tests}/ILMDocumentationIT.java
+
+The Java High Level REST Client supports the following Snapshot Lifecycle
+Management APIs:
+
+* <<{upid}-slm-put-snapshot-lifecycle-policy>>
+* <<{upid}-slm-delete-snapshot-lifecycle-policy>>
+* <<{upid}-ilm-get-lifecycle-policy>>
+* <<{upid}-slm-start-slm>>
+* <<{upid}-slm-stop-slm>>
+* <<{upid}-slm-status>>
+* <<{upid}-slm-execute-snapshot-lifecycle-policy>>
+* <<{upid}-slm-execute-snapshot-lifecycle-retention>>
+
+
+include::ilm/put_snapshot_lifecycle_policy.asciidoc[]
+include::ilm/delete_snapshot_lifecycle_policy.asciidoc[]
+include::ilm/get_snapshot_lifecycle_policy.asciidoc[]
+include::ilm/start_snapshot_lifecycle_management.asciidoc[]
+include::ilm/stop_snapshot_lifecycle_management.asciidoc[]
+include::ilm/snapshot_lifecycle_management_status.asciidoc[]
+include::ilm/execute_snapshot_lifecycle_policy.asciidoc[]
+include::ilm/execute_snapshot_lifecycle_retention.asciidoc[]
+
+
 [role="xpack"]
 [[transform_apis]]
 == {transform-cap} APIs