Apply comments from release notes 3.7.4 to 3.6.6

The release notes review for 3.7.4 (I117b05c912) contains a few
comments that were also applied to version 3.6.6.

Change-Id: Icdf82fdc39f27a59e9d174a10b764775f9c125b0
diff --git a/pages/site/releases/3.6.md b/pages/site/releases/3.6.md
index 03bb8b0..7924402 100644
--- a/pages/site/releases/3.6.md
+++ b/pages/site/releases/3.6.md
@@ -388,13 +388,13 @@
 
     Collision between the sanitized metric names can be easily
     created e.g. `foo_bar` will collide with `foo+bar`. In order
-    to avoid collisions keep the rules about slashes, replace not
-    supported chars with `_0x[HEX CODE]_` string , the
-    replacement prefix `0x` is prepended with another replacement prefix.
+    to avoid collisions keep the rules about slashes and replace not
+    supported chars with `_0x[HEX CODE]_` string. The replacement prefix
+    `0x` is prepended with another replacement prefix.
 
 * New Features
 
-  * [Change 377794](https://gerrit-review.googlesource.com/c/gerrit/+/377794):
+  * [Issue 287484350](https://issues.gerritcodereview.com/issues/287484350):
   Extend configurability of index pagination type
 
     Add NONE option to disable index backend pagination, this option
@@ -438,20 +438,24 @@
     places were adapted.
 
   * [Change 357634](https://gerrit-review.googlesource.com/c/gerrit/+/357634):
-  Release-Notes: Fix parsing legacy labels for users with comma
+  Fix parsing legacy labels for users with comma
 
     This change fixes a bug introduced by [336883](https://gerrit-review.googlesource.com/c/gerrit/+/336883)
     when parsing labels where a UUID was present together with a user name containing a comma.
 
-  * [Change 378558](https://gerrit-review.googlesource.com/c/gerrit/+/378558):
+  * [Issue 289321387](https://issues.gerritcodereview.com/issues/289321387):
   Preserve refs order in the GitBatchRefUpdateEvent event
 
-    [Change 335757](https://gerrit-review.googlesource.com/c/gerrit/+/335757) introduced the concept of the single event
-    representing batch ref update. However this new event did not
-    preserve original order of the updated refs impacting its
-    consumers and potentially causing failures. To make sure that
-    refs order is preserved and backward compatibility is kept use
-    LinkedHashSet instead of HashSet.
+    [Change 335758](https://gerrit-review.googlesource.com/c/gerrit/+/335758)
+    introduced the concept of the single event representing batch ref update.
+    However this new event did not preserve original order of the updated refs.
+    This impacts event consumers behaviour and can cause failures. For example
+    if meta ref is processed before patchset ref indexing operation will
+    fail because of the missing patchset.
+
+    The timeline of events is kept in the same order they are generated,
+    to make sure that refs order is preserved and backward compatibility
+    is kept.
 
 * Documentation fixes