Update release notes for Gerrit v2.16.6

Mention the new setting for restoring the unlimited listing
of projects and the new @LogThreshold annotation for tests.

Change-Id: Ied9423073bdb91c9ce745979837258a585fba015
diff --git a/pages/site/releases/2.16.md b/pages/site/releases/2.16.md
index eb45d12..759ac38 100644
--- a/pages/site/releases/2.16.md
+++ b/pages/site/releases/2.16.md
@@ -512,6 +512,16 @@
   should use when multiple weblink providers are available but only one single
   link may be shown on the UI.
 
+* New configuration option: `gerrit.listProjectsFromIndex`.
+
+  The new configuration option allows restoring the legacy behavior of using
+  the in-memory cache for rendering the list of projects. When set to true
+  the list of projects is rendered using the secondary index and thus is limited
+  by the queryLimits.
+
+  By default is set to false, the in-memory cache is used as an engine for listing
+  and thus returns all the projects without limits.
+
 #### PolyGerrit UI changes
 
 * Gitiles change-weblink with default weblink name ("browse") is now inline.
@@ -523,6 +533,11 @@
   displayed inline (href of current patchset and parent SHA1s) unless gitweb
   is available and configured as gerrit.primaryWeblinkName.
 
+#### Plugins API
+
+* New annotation @LogThreshold for setting a logging level during the execution
+  of the tests. By default is set to DEBUG for backward compatibility.
+
 #### Bug fixes
 
 ##### PolyGerrit