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/y2019/jevois/uart_test.cc b/y2019/jevois/uart_test.cc
index 5a3a330..621412d 100644
--- a/y2019/jevois/uart_test.cc
+++ b/y2019/jevois/uart_test.cc
@@ -4,9 +4,7 @@
 
 #include "gtest/gtest.h"
 
-namespace frc971 {
-namespace jevois {
-namespace testing {
+namespace frc971::jevois::testing {
 
 // Tests packing and then unpacking a message with arbitrary values.
 TEST(UartToTeensyTest, Basic) {
@@ -123,6 +121,4 @@
   }
 }
 
-}  // namespace testing
-}  // namespace jevois
-}  // namespace frc971
+}  // namespace frc971::jevois::testing