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/autonomous/autonomous_actor.cc b/y2023/autonomous/autonomous_actor.cc
index e452d21..652fe66 100644
--- a/y2023/autonomous/autonomous_actor.cc
+++ b/y2023/autonomous/autonomous_actor.cc
@@ -17,8 +17,7 @@
 DEFINE_bool(charged_up_cable, false, "If true run cable side autonomous mode");
 DEFINE_bool(do_balance, true, "If true run the balance.");
 
-namespace y2023 {
-namespace autonomous {
+namespace y2023::autonomous {
 
 using ::frc971::ProfileParametersT;
 
@@ -629,5 +628,4 @@
   return true;
 }
 
-}  // namespace autonomous
-}  // namespace y2023
+}  // namespace y2023::autonomous