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/action_joystick_input.cc b/frc971/input/action_joystick_input.cc
index dfd229e..ae3346c 100644
--- a/frc971/input/action_joystick_input.cc
+++ b/frc971/input/action_joystick_input.cc
@@ -8,8 +8,7 @@
 
 using ::frc971::input::driver_station::ControlBit;
 
-namespace frc971 {
-namespace input {
+namespace frc971::input {
 
 void ActionJoystickInput::RunIteration(
     const ::frc971::input::driver_station::Data &unsorted_data) {
@@ -74,5 +73,4 @@
   AutoEnded();
 }
 
-}  // namespace input
-}  // namespace frc971
+}  // namespace frc971::input
diff --git a/frc971/input/driver_station_data.cc b/frc971/input/driver_station_data.cc
index 18d96fd..06d2d69 100644
--- a/frc971/input/driver_station_data.cc
+++ b/frc971/input/driver_station_data.cc
@@ -2,9 +2,7 @@
 
 #include "glog/logging.h"
 
-namespace frc971 {
-namespace input {
-namespace driver_station {
+namespace frc971::input::driver_station {
 
 Data::Data() : current_values_(), old_values_() {}
 
@@ -119,6 +117,4 @@
   return current_values_.joysticks[axis.joystick() - 1].axis[axis.number() - 1];
 }
 
-}  // namespace driver_station
-}  // namespace input
-}  // namespace frc971
+}  // namespace frc971::input::driver_station
diff --git a/frc971/input/drivetrain_input.cc b/frc971/input/drivetrain_input.cc
index 5aedd0e..be61cc4 100644
--- a/frc971/input/drivetrain_input.cc
+++ b/frc971/input/drivetrain_input.cc
@@ -18,8 +18,7 @@
 
 namespace drivetrain = frc971::control_loops::drivetrain;
 
-namespace frc971 {
-namespace input {
+namespace frc971::input {
 
 const ButtonLocation kShiftHigh(2, 3), kShiftHigh2(2, 2), kShiftLow(2, 1);
 
@@ -371,5 +370,4 @@
   return drivetrain_input_reader;
 }
 
-}  // namespace input
-}  // namespace frc971
+}  // namespace frc971::input
diff --git a/frc971/input/joystick_input.cc b/frc971/input/joystick_input.cc
index d0d9bc0..19eaa37 100644
--- a/frc971/input/joystick_input.cc
+++ b/frc971/input/joystick_input.cc
@@ -6,8 +6,7 @@
 #include "aos/logging/logging.h"
 #include "frc971/input/robot_state_generated.h"
 
-namespace frc971 {
-namespace input {
+namespace frc971::input {
 
 void JoystickInput::HandleData(const ::aos::JoystickState *joystick_state) {
   data_.Update(joystick_state);
@@ -60,5 +59,4 @@
   RunIteration(data_);
 }
 
-}  // namespace input
-}  // namespace frc971
+}  // namespace frc971::input
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