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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/zeroing/continuous_absolute_encoder.cc b/frc971/zeroing/continuous_absolute_encoder.cc
index a47a491..ebaf101 100644
--- a/frc971/zeroing/continuous_absolute_encoder.cc
+++ b/frc971/zeroing/continuous_absolute_encoder.cc
@@ -8,8 +8,7 @@
 #include "aos/containers/error_list.h"
 #include "frc971/zeroing/wrap.h"
 
-namespace frc971 {
-namespace zeroing {
+namespace frc971::zeroing {
 
 ContinuousAbsoluteEncoderZeroingEstimator::
     ContinuousAbsoluteEncoderZeroingEstimator(
@@ -165,5 +164,4 @@
   return builder.Finish();
 }
 
-}  // namespace zeroing
-}  // namespace frc971
+}  // namespace frc971::zeroing