Add comment for per-app preference priority

Clarify that only the highest priority preference is applied if the uid
is target of multiple preferences.

Test: TH
Change-Id: I55b6a37995bcfe876ed609cf653077df2b5e7615
diff --git a/service/src/com/android/server/ConnectivityService.java b/service/src/com/android/server/ConnectivityService.java
index a34c0a9..dc91f7d 100755
--- a/service/src/com/android/server/ConnectivityService.java
+++ b/service/src/com/android/server/ConnectivityService.java
@@ -552,6 +552,8 @@
      * default network for each app.
      * Order ints passed to netd must be in the 0~999 range. Larger values code for
      * a lower priority, see {@link NativeUidRangeConfig}.
+     * Note that only the highest priority preference is applied if the uid is the target of
+     * multiple preferences.
      *
      * Requests that don't code for a per-app preference use PREFERENCE_ORDER_INVALID.
      * The default request uses PREFERENCE_ORDER_DEFAULT.