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/spi_test.cc b/y2019/jevois/spi_test.cc
index c600869..3c69993 100644
--- a/y2019/jevois/spi_test.cc
+++ b/y2019/jevois/spi_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 an empty message.
 TEST(SpiToRoborioPackTest, Empty) {
@@ -228,6 +226,4 @@
   EXPECT_EQ(input_message, output_message.value());
 }
 
-}  // namespace testing
-}  // namespace jevois
-}  // namespace frc971
+}  // namespace frc971::jevois::testing