Update search.asciidoc (#28646)

[DOCS] Corrected typo - singe to single.

docs/reference/search/search.asciidoc

@@ -70,7 +70,7 @@ to reject search requests that hit too many shards.
 
 The search's `max_concurrent_shard_requests` request parameter can be used to control
 the maximum number of concurrent shard requests the search API will execute for this request.
-This parameter should be used to protect a singe request from overloading a cluster ie. a default
+This parameter should be used to protect a single request from overloading a cluster ie. a default
 request will hit all indices in a cluster which could cause shard request rejections if the
 number of shards per node is high. This default is based on the number of data nodes in
-the cluster but at most `256`.
+the cluster but at most `256`.