Finalize release notes for v8.16.4

Author: elasticsearchmachine

docs/reference/release-notes/8.16.4.asciidoc

@@ -1,8 +1,6 @@
 [[release-notes-8.16.4]]
 == {es} version 8.16.4
 
-coming[8.16.4]
-
 Also see <<breaking-changes-8.16,Breaking changes in 8.16>>.
 
 [[bug-8.16.4]]