Clarify that annotations are only supported on email and per-file lines

By linking to the access grants section we made the wrong impression
that annotations would also work for other lines such as file or include
lines.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: Idcc8c0c479ece6f65b9fec47dd084298d479fae5
diff --git a/resources/Documentation/backend-find-owners.md b/resources/Documentation/backend-find-owners.md
index c2eaeea..9d2fab5 100644
--- a/resources/Documentation/backend-find-owners.md
+++ b/resources/Documentation/backend-find-owners.md
@@ -313,8 +313,9 @@
 
 ### <a id="anotations">Annotations
 
-Lines representing [access grants](#accessGrants) can be annotated. Annotations
-have the format `#{ANNOTATION_NAME}` and can appear at the end of the line.
+Lines that assign code ownership to users ([email lines](#userEmails) and
+[per-file lines](#perFile)) can be annotated. Annotations have the format
+`#{ANNOTATION_NAME}` and can appear at the end of the line.
 E.g.:
 
 ```
@@ -344,9 +345,14 @@
 
 Unknown annotations are silently ignored.
 
-**NOTE:** If an access grant line that assigns code ownership to multiple users
-has an annotation, this annotation applies to all these users. E.g. if an
-annotation is set for the all users wildcard (aka `*`) it applies to all users.
+**NOTE:** If a line that assigns code ownership to multiple users has an
+annotation, this annotation applies to all these users. E.g. if an annotation is
+set for the all users wildcard (aka `*`) it applies to all users.
+
+**NOTE:** Only [email lines](#userEmails) and [per-file lines](#perFile) support
+annotations, for other lines (e.g. [file lines](#fileKeyword) and [include
+lines](#includeKeyword)) annotations are interpreted as [comments](#comments)
+and are silently ignored.
 
 ### <a id="comments">Comments