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/logging/interface.cc b/aos/logging/interface.cc
index 233357d..e0ce6a8 100644
--- a/aos/logging/interface.cc
+++ b/aos/logging/interface.cc
@@ -12,8 +12,7 @@
 #include "aos/logging/context.h"
 #include "aos/logging/implementations.h"
 
-namespace aos {
-namespace logging {
+namespace aos::logging {
 namespace internal {
 
 size_t ExecuteFormat(char *output, size_t output_size, const char *format,
@@ -62,8 +61,7 @@
   }
 }
 
-}  // namespace logging
-}  // namespace aos
+}  // namespace aos::logging
 
 void log_do(log_level level, const char *format, ...) {
   va_list ap;