Document another case where no code owners are suggested

Code owners that cannot see the change, and hence cannot approve it, are
filtered out from the code owner suggestion. This means if none of the
code owners can see the change, the list of suggested code owners is
empty. In this case the frontend is showing an info icons that links to
the documentation that explains the cases when this happens. Update this
documentation to include the case where none of the code owners can see
the change.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I705fc962a43f423fc0950e80096effae5a270608
diff --git a/resources/Documentation/how-to-use.md b/resources/Documentation/how-to-use.md
index d412c2c..23337be 100644
--- a/resources/Documentation/how-to-use.md
+++ b/resources/Documentation/how-to-use.md
@@ -151,20 +151,25 @@
 
 ![no owners found](./no-owners-found.png "no owners found")
 
-- No owners were defined for these files.
+- No code owners were defined for these files.
   Reason: This could be due to missing `OWNERS` defined for these files.
 
 - None of the code owners of these files are visible.
   Reason: The code owners accounts are not visible to you.
 
+- None of the code owners can see the change.
+  Reason: The code owners have no read permission on the target branch of the
+  change and hence cannot approve the change.
+
 - Code owners defined for these files are invalid.
   Reason: The emails cannot be resolved.
 
-For these 3 cases, we advise you to:
+For these cases, we advise you to:
 
 1. Ask someone with override powers (e.g. sheriff) to grant an override vote to
    unblock the change submission.
-2. Contact the project owner to ask them to fix the code owner definitions.
+2. Contact the project owner to ask them to fix the code owner definitions, or
+   permissions if needed.
 
 ### Renamed files