ls-groups: Add option to only list groups that are visible to all

Change-Id: I68a9ec5397f9e314bc582844c620722641702154
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/Documentation/cmd-ls-groups.txt b/Documentation/cmd-ls-groups.txt
index cb65f7e..78b2f2e 100644
--- a/Documentation/cmd-ls-groups.txt
+++ b/Documentation/cmd-ls-groups.txt
@@ -10,6 +10,7 @@
 [verse]
 'ssh' -p <port> <host> 'gerrit ls-groups'
   [--project <NAME>]
+  [--visible-to-all]
 
 DESCRIPTION
 -----------
@@ -38,6 +39,11 @@
 	projects. In this case all groups are listed that have a
 	permission for any of the specified projects.
 
+--visible-to-all::
+	Displays only groups that are visible to all registered users
+	(groups that are explicitly marked as visible to all registered
+	users).
+
 EXAMPLES
 --------