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/y2020/joystick_reader.cc b/y2020/joystick_reader.cc
index 951c5a7..2aa263e 100644
--- a/y2020/joystick_reader.cc
+++ b/y2020/joystick_reader.cc
@@ -31,9 +31,7 @@
 using frc971::control_loops::CreateStaticZeroingSingleDOFProfiledSubsystemGoal;
 using frc971::control_loops::StaticZeroingSingleDOFProfiledSubsystemGoal;
 
-namespace y2020 {
-namespace input {
-namespace joysticks {
+namespace y2020::input::joysticks {
 
 namespace superstructure = y2020::control_loops::superstructure;
 
@@ -332,9 +330,7 @@
   size_t unwinch_counter_ = 0;
 };
 
-}  // namespace joysticks
-}  // namespace input
-}  // namespace y2020
+}  // namespace y2020::input::joysticks
 
 int main(int argc, char **argv) {
   ::aos::InitGoogle(&argc, &argv);