Nest all namespaces

The compiler supports this now.  We can type less going forward.
No functional changes.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I29d6fa4f9aacc0e381f1a7637294db0392466995
diff --git a/frc971/input/redundant_joystick_data.cc b/frc971/input/redundant_joystick_data.cc
index a25e6c3..752239d 100644
--- a/frc971/input/redundant_joystick_data.cc
+++ b/frc971/input/redundant_joystick_data.cc
@@ -2,9 +2,7 @@
 
 #include "aos/logging/logging.h"
 
-namespace frc971 {
-namespace input {
-namespace driver_station {
+namespace frc971::input::driver_station {
 
 RedundantData::RedundantData(const Data &data) : joystick_map_(), data_(data) {
   // Start with a naive map.
@@ -98,6 +96,4 @@
   return data_.GetAxis(mapped_location);
 }
 
-}  // namespace driver_station
-}  // namespace input
-}  // namespace frc971
+}  // namespace frc971::input::driver_station