Nest some more namespaces

Did someone previously suggest that all namespace had been
nested?  Silly.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I22278c1caaeba8b47dc46fb2ed3078c20a11e190
diff --git a/y2019/control_loops/superstructure/vacuum.h b/y2019/control_loops/superstructure/vacuum.h
index c4671ab..58ad109 100644
--- a/y2019/control_loops/superstructure/vacuum.h
+++ b/y2019/control_loops/superstructure/vacuum.h
@@ -7,9 +7,7 @@
 #include "y2019/control_loops/superstructure/superstructure_goal_generated.h"
 #include "y2019/control_loops/superstructure/superstructure_output_generated.h"
 
-namespace y2019 {
-namespace control_loops {
-namespace superstructure {
+namespace y2019::control_loops::superstructure {
 
 class Vacuum {
  public:
@@ -55,8 +53,6 @@
   DISALLOW_COPY_AND_ASSIGN(Vacuum);
 };
 
-}  // namespace superstructure
-}  // namespace control_loops
-}  // namespace y2019
+}  // namespace y2019::control_loops::superstructure
 
 #endif  // Y2019_CONTROL_LOOPS_SUPERSTRUCTURE_SUPERSTRUCTURE_H_