Rolling restart instructions (#82387)

* Rolling restart instructions

In a rolling restart scenario, indexing do not need to be stopped. This step is optional. I have updated Rolling restart/ step 2.

Note: I am not sure how to check if the doc, once generated, will keep the numbering as section 1 and 3 are references to the full restart, can you check this detail?

* Clarify that shard recovery can be faster

Co-authored-by: Adam Locke <adam.locke@elastic.co>

docs/reference/setup/restart-cluster.asciidoc

@@ -173,7 +173,18 @@ the datafeeds from {kib} or with the <<ml-open-job,open jobs>> and
 
 include::{es-repo-dir}/setup/restart-cluster.asciidoc[tag=disable_shard_alloc]
 
-include::{es-repo-dir}/setup/restart-cluster.asciidoc[tag=stop_indexing]
+. *Stop non-essential indexing and perform a flush.* (Optional)
++
+--
+While you can continue indexing during the rolling restart, shard recovery
+can be faster if you temporarily stop non-essential indexing and perform a
+<<indices-flush, flush>>.
+
+[source,console]
+--------------------------------------------------
+POST /_flush
+--------------------------------------------------
+--
 
 include::{es-repo-dir}/setup/restart-cluster.asciidoc[tag=stop_ml]
 +