Describe most important documentation updates in 2.9 release notes

Change-Id: I9ec569969c1782373bc93e049e35911406b442c9
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

ReleaseNotes/ReleaseNotes-2.9.txt

diff --git a/ReleaseNotes/ReleaseNotes-2.9.txt b/ReleaseNotes/ReleaseNotes-2.9.txt
index f1585b1..b5a18d8 100644
--- a/ReleaseNotes/ReleaseNotes-2.9.txt
+++ b/ReleaseNotes/ReleaseNotes-2.9.txt
@@ -95,6 +95,26 @@
 New `-s` option is added to the Daemon to start an interactive Jython shell for inspection and
 troubleshooting of live data of the Gerrit instance.
 
+Documentation
+~~~~~~~~~~~~~
+
+
+* The documentation is now
+https://gerrit-documentation.storage.googleapis.com/Documentation/2.9/rest-api-documentation.html#search-documentation.html[
+searchable]:
++
+On each documentation page there is search box in the right top corner
+that allows to search in the documentation.
+
+* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.9/user-review-ui.html[
+Documentation of the new review UI]
+
+* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.9/intro-project-owner.html[
+New Project Owner Guide]
+
+* link:https://gerrit-documentation.storage.googleapis.com/Documentation/2.9/index.html[
+Newly structured documentation index]
+
 Plugins
 ~~~~~~~