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/vision/intrinsics_calibration_lib.h b/frc971/vision/intrinsics_calibration_lib.h
index 3076ed9..7f08138 100644
--- a/frc971/vision/intrinsics_calibration_lib.h
+++ b/frc971/vision/intrinsics_calibration_lib.h
@@ -16,8 +16,7 @@
 #include "aos/util/file.h"
 #include "frc971/vision/charuco_lib.h"
 
-namespace frc971 {
-namespace vision {
+namespace frc971::vision {
 
 class IntrinsicsCalibration {
  public:
@@ -76,6 +75,5 @@
   aos::ExitHandle *exit_handle_;
 };
 
-}  // namespace vision
-}  // namespace frc971
+}  // namespace frc971::vision
 #endif  // FRC971_VISION_CALIBRATION_LIB_H_