[DOCS] Remove coming tag from 8.0.0-alpha2 RNs (elastic#1754)

Author: jrodewig

docs/src/reference/asciidoc/appendix/release-notes/8.0.0-alpha2.adoc

@@ -1,7 +1,5 @@
 [[eshadoop-8.0.0-alpha2]]
 == Elasticsearch for Apache Hadoop version 8.0.0-alpha2
 
-coming::[8.0.0-alpha2]
-
 ES-Hadoop 8.0.0-alpha2 is a version compatibility release, tested specifically
 against Elasticsearch 8.0.0-alpha2.