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/wpilib_interface.cc b/y2018/wpilib_interface.cc
index cf71bdd..32ef7a9 100644
--- a/y2018/wpilib_interface.cc
+++ b/y2018/wpilib_interface.cc
@@ -63,8 +63,7 @@
 namespace chrono = ::std::chrono;
 namespace superstructure = ::y2018::control_loops::superstructure;
 
-namespace y2018 {
-namespace wpilib {
+namespace y2018::wpilib {
 namespace {
 
 constexpr double kMaxBringupPower = 12.0;
@@ -779,7 +778,6 @@
 };
 
 }  // namespace
-}  // namespace wpilib
-}  // namespace y2018
+}  // namespace y2018::wpilib
 
 AOS_ROBOT_CLASS(::y2018::wpilib::WPILibRobot);