health: update comments.

Test: pass
Bug: 63702641
Change-Id: Iedf1bfe37a356e5801a09e313ac186fdc73668ca
diff --git a/health/2.0/libhealthhalutils/Android.bp b/health/2.0/libhealthhalutils/Android.bp
index 1bd934b..5686520 100644
--- a/health/2.0/libhealthhalutils/Android.bp
+++ b/health/2.0/libhealthhalutils/Android.bp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+// Convenience library for (hwbinder) clients to choose the correct health
+// service instance.
 cc_library_static {
     name: "libhealthhalutils",
     srcs: ["HealthHalUtils.cpp"],