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/y2018/joystick_reader.cc b/y2018/joystick_reader.cc
index 7e25bb3..351d1f5 100644
--- a/y2018/joystick_reader.cc
+++ b/y2018/joystick_reader.cc
@@ -38,9 +38,7 @@
 using ::y2018::control_loops::superstructure::arm::BackPoints;
 using ::y2018::control_loops::superstructure::arm::FrontPoints;
 
-namespace y2018 {
-namespace input {
-namespace joysticks {
+namespace y2018::input::joysticks {
 
 namespace arm = ::y2018::control_loops::superstructure::arm;
 
@@ -386,9 +384,7 @@
   ::std::unique_ptr<ProtoTXUdpSocket<VisionControl>> video_tx_;
 };
 
-}  // namespace joysticks
-}  // namespace input
-}  // namespace y2018
+}  // namespace y2018::input::joysticks
 
 int main(int argc, char **argv) {
   ::aos::InitGoogle(&argc, &argv);