[DOCS] Tolerate more cluster names in docs tests
The name of the cluster used for testing the docs
varies between versions.  This change makes the
assertion on the cluster name more tolerant of
variations.
Relates
@@ -163,7 +163,7 @@ is _green_ and it has three nodes:
epoch timestamp cluster status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1565052807 00:53:27 elasticsearch green 3 3 6 3 0 0 0 0 - 100.0%
--------------------------------------------------
-// TESTRESPONSE[s/1565052807 00:53:27 elasticsearch/\\d+ \\d+:\\d+:\\d+ integTest/]
+// TESTRESPONSE[s/1565052807 00:53:27 elasticsearch/\\d+ \\d+:\\d+:\\d+ \\w*integTest\\w*/]
// TESTRESPONSE[s/3 3 6 3/\\d+ \\d+ \\d+ \\d+/]
// TESTRESPONSE[s/0 0 -/0 \\d+ -/]
// TESTRESPONSE[non_json]
