Merge pull request #5539 from grpc/makdharma-comment

Update reconnect_interop_server.cc
diff --git a/test/cpp/interop/reconnect_interop_server.cc b/test/cpp/interop/reconnect_interop_server.cc
index 3602b8c..785f9c7 100644
--- a/test/cpp/interop/reconnect_interop_server.cc
+++ b/test/cpp/interop/reconnect_interop_server.cc
@@ -30,6 +30,8 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
+ 
+// Test description at doc/connection-backoff-interop-test-description.md
 
 #include <signal.h>
 #include <unistd.h>