[DOCS] Clarify title for X-Pack install
Original commit: elastic/x-pack-elasticsearch@56e332fb342705554085cf6f9b87a4fe45f6d4f0
[role="xpack"]
[[installing-xpack-es]]
-== Installing X-Pack
+== Installing X-Pack in Elasticsearch
+++++
+<titleabbrev>Installing {xpack}</titleabbrev>
+++++
After you install {es}, you can optionally obtain and install {xpack}.
For more information about how to obtain {xpack},
