Document that private changes are visibile to users with 'View Private Changes'

Change-Id: Ia5383d8a63990f0ae8e666999ecadd398462865a
Signed-off-by: Edwin Kempin <ekempin@google.com>

Documentation/intro-user.txt

diff --git a/Documentation/intro-user.txt b/Documentation/intro-user.txt
index 6242fcf..b20c2c0 100644
--- a/Documentation/intro-user.txt
+++ b/Documentation/intro-user.txt
@@ -531,8 +531,10 @@
 [[private-changes]]
 == Private Changes
 
-Private changes are changes that are only visible to their owners and
-reviewers. Private changes are useful in a number of cases:
+Private changes are changes that are only visible to their owners, reviewers
+and users with the link:access-control.html#category_view_private_changes[
+View Private Changes] global capability. Private changes are useful in a number
+of cases:
 
 * You want to check what the change looks like before formal review starts.
   By marking the change private without reviewers, nobody can