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/y2024/autonomous/autonomous_actor.cc b/y2024/autonomous/autonomous_actor.cc
index fd42a56..a7c656d 100644
--- a/y2024/autonomous/autonomous_actor.cc
+++ b/y2024/autonomous/autonomous_actor.cc
@@ -13,8 +13,7 @@
 
 DEFINE_bool(spline_auto, false, "Run simple test S-spline auto mode.");
 
-namespace y2024 {
-namespace autonomous {
+namespace y2024::autonomous {
 
 using ::frc971::ProfileParametersT;
 
@@ -192,5 +191,4 @@
     AOS_LOG(ERROR, "Failed to reset localizer.\n");
   }
 }
-}  // namespace autonomous
-}  // namespace y2024
+}  // namespace y2024::autonomous