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/frc971/constants.h b/frc971/constants.h
index 0367937..48b8ca9 100644
--- a/frc971/constants.h
+++ b/frc971/constants.h
@@ -6,8 +6,7 @@
 #include "frc971/control_loops/control_loops_generated.h"
 #include "frc971/zeroing/constants_generated.h"
 
-namespace frc971 {
-namespace constants {
+namespace frc971::constants {
 
 typedef frc971::zeroing::HallEffectZeroingConstantsT HallEffectZeroingConstants;
 
@@ -53,7 +52,6 @@
   }
 };
 
-}  // namespace constants
-}  // namespace frc971
+}  // namespace frc971::constants
 
 #endif  // FRC971_CONSTANTS_H_