Update setFrameRate documentation

Add a link to how to listen to the change in frame rate.

Bug: 186657402
Test: n/a
Change-Id: Idb04f966906964a98a744d914e5aca2b1db4ee46
diff --git a/include/android/surface_control.h b/include/android/surface_control.h
index b7eafcd..a6cf353 100644
--- a/include/android/surface_control.h
+++ b/include/android/surface_control.h
@@ -526,6 +526,9 @@
  * callback timings, and changes to the time interval at which the system releases buffers back to
  * the application.
  *
+ * You can register for changes in the refresh rate using
+ * \a AChoreographer_registerRefreshRateCallback.
+ *
  * \param frameRate is the intended frame rate of this surface, in frames per second. 0 is a special
  * value that indicates the app will accept the system's choice for the display frame rate, which is
  * the default behavior if this function isn't called. The frameRate param does <em>not</em> need to