Nest all namespaces

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/y2022/vision/camera_reader.cc b/y2022/vision/camera_reader.cc
index 012a2db..a077d09 100644
--- a/y2022/vision/camera_reader.cc
+++ b/y2022/vision/camera_reader.cc
@@ -17,8 +17,7 @@
 
 DEFINE_string(image_png, "", "A set of PNG images");
 
-namespace y2022 {
-namespace vision {
+namespace y2022::vision {
 
 using namespace frc971::vision;
 
@@ -235,5 +234,4 @@
   }
 }
 
-}  // namespace vision
-}  // namespace y2022
+}  // namespace y2022::vision