Update release-notes.asciidoc

Author: charlotte-hoblik

docs/reference/release-notes.asciidoc

@@ -6,7 +6,6 @@
 
 This section summarizes the changes in each release.
 
-* <<release-notes-8.19.4>>
 * <<release-notes-8.19.3>>
 * <<release-notes-8.19.2>>
 * <<release-notes-8.19.1>>
@@ -105,7 +104,6 @@ This section summarizes the changes in each release.
 
 --
 
-include::release-notes/8.19.4.asciidoc[]
 include::release-notes/8.19.3.asciidoc[]
 include::release-notes/8.19.2.asciidoc[]
 include::release-notes/8.19.1.asciidoc[]