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/frc971/zeroing/continuous_absolute_encoder.h b/frc971/zeroing/continuous_absolute_encoder.h
index e11d866..4994280 100644
--- a/frc971/zeroing/continuous_absolute_encoder.h
+++ b/frc971/zeroing/continuous_absolute_encoder.h
@@ -8,8 +8,7 @@
 #include "aos/containers/error_list.h"
 #include "frc971/zeroing/zeroing.h"
 
-namespace frc971 {
-namespace zeroing {
+namespace frc971::zeroing {
 
 // Estimates the position with an absolute encoder which spins continuously. The
 // absolute encoder must have a 1:1 ratio to the output.
@@ -93,7 +92,6 @@
   aos::ErrorList<ZeroingError> errors_;
 };
 
-}  // namespace zeroing
-}  // namespace frc971
+}  // namespace frc971::zeroing
 
 #endif  // FRC971_ZEROING_CONTINUOUS_ABSOLUTE_ENCODER_H_