Add Deprecation tag to arcsight module (#17331) (#17334)

(cherry picked from commit d45706d)

Co-authored-by: Rob Bavey <[email protected]>

Author: mergify[bot]

docs/static/arcsight-module.asciidoc

@@ -6,6 +6,8 @@
 <titleabbrev>ArcSight Module</titleabbrev>
 ++++
 
+deprecated[8.16.0]
+
 NOTE: The Logstash ArcSight module is an
 https://www.elastic.co/products/x-pack[{xpack}] feature under the Basic License
 and is therefore free to use. Please contact