Document that being a code owner doesn't grant the user permissions to approve

Configuring code owners and configuring permissions to approve are
orthogonal things. Document this so that users get aware of this and
don't have wrong expectations.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: Ife0cb7fbd455c8778d70447856d1382892dad6d1
diff --git a/resources/Documentation/user-guide.md b/resources/Documentation/user-guide.md
index 37049fc..a176398 100644
--- a/resources/Documentation/user-guide.md
+++ b/resources/Documentation/user-guide.md
@@ -24,6 +24,12 @@
 Who is a code owner of a path is controlled via [code owner config
 files](#codeOwnerConfigFiles) (e.g. `OWNERS` files).
 
+**NOTE:** Being a code owner doesn't grant the user permissions to approve
+changes, but permissions to vote on the label that is required as a
+[code owner approval](#codeOwnerApproval) must be configured separately. This
+means it's possible that a user is a code owner, but misses permissions to apply
+code owner approvals.
+
 ## <a id="whyCodeOwners">Why should code owners be used?
 
 Code owners are gatekeepers before a change is submitted, they enforce standards