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/v4l2_reader.h b/frc971/vision/v4l2_reader.h
index 6338ba5..a3d6252 100644
--- a/frc971/vision/v4l2_reader.h
+++ b/frc971/vision/v4l2_reader.h
@@ -16,8 +16,7 @@
 #include "aos/util/threaded_consumer.h"
 #include "frc971/vision/vision_generated.h"
 
-namespace frc971 {
-namespace vision {
+namespace frc971::vision {
 
 // Reads images from a V4L2 capture device (aka camera).
 class V4L2ReaderBase {
@@ -199,7 +198,6 @@
   aos::util::ThreadedConsumer<int, kNumberBuffers> buffer_requeuer_;
 };
 
-}  // namespace vision
-}  // namespace frc971
+}  // namespace frc971::vision
 
 #endif  // FRC971_VISION_V4L2_READER_H_