Update 2.6 release notes with more trivial_rebase fixes

Change-Id: Ifda8ff4f92ffc620b5b668402a7f3cb9109847eb
diff --git a/ReleaseNotes/ReleaseNotes-2.6.txt b/ReleaseNotes/ReleaseNotes-2.6.txt
index f73c306..e293936 100644
--- a/ReleaseNotes/ReleaseNotes-2.6.txt
+++ b/ReleaseNotes/ReleaseNotes-2.6.txt
@@ -1517,6 +1517,15 @@
 ** Use change-url flag for ChangeId
 ** Prevent exception for empty commit
 ** Fix pylint errors
+** Call `gerrit review` instead of `gerrit approve`
+** Make the private key argument optional
+** Support alternative ssh executable, for example `plink`
+** Support custom review labels
+** Correctly handle empty patch ID
++
+If only one of the patch IDs is empty, it should not be considered
+a trivial rebase.
+
 ** Use plain python instead of python2.6
 +
 Windows installation only has python.exe