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/y2023/tof_controller/tof_controller.cc b/y2023/tof_controller/tof_controller.cc
index f8e8fb9..80102ae 100644
--- a/y2023/tof_controller/tof_controller.cc
+++ b/y2023/tof_controller/tof_controller.cc
@@ -13,8 +13,7 @@
 #include "pico/bootrom.h"
 #include "pico/stdlib.h"
 
-namespace y2023 {
-namespace tof_controller {
+namespace y2023::tof_controller {
 
 static constexpr uint kI2CBaudrate = 100000;
 static constexpr uint16_t kExpectedSensorId = 0xEBAA;
@@ -500,7 +499,6 @@
   }
 }
 
-}  // namespace tof_controller
-}  // namespace y2023
+}  // namespace y2023::tof_controller
 
 int main() { y2023::tof_controller::main(); }