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/wpilib/sensor_reader.h b/frc971/wpilib/sensor_reader.h
index bf8c96a..455ed0e 100644
--- a/frc971/wpilib/sensor_reader.h
+++ b/frc971/wpilib/sensor_reader.h
@@ -21,8 +21,7 @@
 using ::aos::monotonic_clock;
 namespace chrono = ::std::chrono;
 
-namespace frc971 {
-namespace wpilib {
+namespace frc971::wpilib {
 
 class SensorReader {
  public:
@@ -264,7 +263,6 @@
   chrono::microseconds period_ = chrono::microseconds(5000);
 };
 
-}  // namespace wpilib
-}  // namespace frc971
+}  // namespace frc971::wpilib
 
 #endif  // FRC971_WPILIB_SENSOR_READER_H_