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/constants.h b/y2023/constants.h
index 92428db..402fc73 100644
--- a/y2023/constants.h
+++ b/y2023/constants.h
@@ -15,8 +15,7 @@
 #include "y2023/control_loops/superstructure/roll/roll_plant.h"
 #include "y2023/control_loops/superstructure/wrist/wrist_plant.h"
 
-namespace y2023 {
-namespace constants {
+namespace y2023::constants {
 
 constexpr uint16_t kCompTeamNumber = 971;
 constexpr uint16_t kPracticeTeamNumber = 9971;
@@ -236,7 +235,6 @@
 // Calls MakeValues with aos::network::GetTeamNumber()
 Values MakeValues();
 
-}  // namespace constants
-}  // namespace y2023
+}  // namespace y2023::constants
 
 #endif  // Y2023_CONSTANTS_H_