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/aos/events/logging/logfile_utils_test.cc b/aos/events/logging/logfile_utils_test.cc
index ea56d8d..30a0ada 100644
--- a/aos/events/logging/logfile_utils_test.cc
+++ b/aos/events/logging/logfile_utils_test.cc
@@ -22,9 +22,7 @@
 #include "aos/testing/tmpdir.h"
 #include "aos/util/file.h"
 
-namespace aos {
-namespace logger {
-namespace testing {
+namespace aos::logger::testing {
 namespace chrono = std::chrono;
 using aos::message_bridge::RemoteMessage;
 using aos::testing::ArtifactPath;
@@ -3386,6 +3384,4 @@
   }
 }
 
-}  // namespace testing
-}  // namespace logger
-}  // namespace aos
+}  // namespace aos::logger::testing