Fix clone API settings docs bug (#74175)

In #74138 we noted that index settings aren't copied in a clone. In fact
that's not true, we copy everything except explicitly-excluded ones,
`number_of_replicas` and `auto_expand_replicas`. This fixes the mistake.

Co-authored-by: James Rodewig <[email protected]>

Author: DaveCTurner

docs/reference/indices/clone-index.asciidoc

@@ -56,12 +56,20 @@ and then the previous write index can be cloned.
 Use the clone index API to clone an existing index into a new index, where each
 original primary shard is cloned into a new primary shard in the new index.
 
-IMPORTANT: {es} doesn't apply index templates to the resulting index. The API
-also doesn't copy index settings or metadata from the original index. Index
-metadata includes aliases, {ilm-init} phase definitions, and {ccr-init} follower
+[IMPORTANT]
+====
+{es} doesn't apply index templates to the resulting index. The API
+also doesn't copy index metadata from the original index. Index metadata
+includes aliases, {ilm-init} phase definitions, and {ccr-init} follower
 information. For example, if you clone a {ccr-init} follower index, the
 resulting clone won't be a follower index.
 
+The clone API copies most index settings from the source index to the resulting
+index, with the exception of `index.number_of_replicas` and
+`index.auto_expand_replicas`. To set the number of replicas in the resulting
+index, configure these settings in the clone request.
+====
+
 [[cloning-works]]
 ===== How cloning works