Nest some more namespaces

Did someone previously suggest that all namespace had been
nested?  Silly.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I22278c1caaeba8b47dc46fb2ed3078c20a11e190
diff --git a/y2023/vision/aprilrobotics.h b/y2023/vision/aprilrobotics.h
index 123f352..e11bfcc 100644
--- a/y2023/vision/aprilrobotics.h
+++ b/y2023/vision/aprilrobotics.h
@@ -21,8 +21,7 @@
 #include "frc971/vision/visualize_robot.h"
 #include "y2023/constants/constants_generated.h"
 
-namespace y2023 {
-namespace vision {
+namespace y2023::vision {
 
 class AprilRoboticsDetector {
  public:
@@ -97,5 +96,4 @@
   frc971::vision::VisualizeRobot vis_robot_;
 };
 
-}  // namespace vision
-}  // namespace y2023
+}  // namespace y2023::vision