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/motors/print/itm.h b/motors/print/itm.h
index 64e3092..05ffb2c 100644
--- a/motors/print/itm.h
+++ b/motors/print/itm.h
@@ -5,8 +5,7 @@
 
 #include "motors/print/print.h"
 
-namespace frc971 {
-namespace motors {
+namespace frc971::motors {
 
 // A printing implementation via the SWO (trace output) pin. This requires an
 // attached debugger which is in SWD (Single Wire Debug) mode, has the SWO
@@ -28,7 +27,6 @@
   int WriteDebug(absl::Span<const char> buffer) override;
 };
 
-}  // namespace motors
-}  // namespace frc971
+}  // namespace frc971::motors
 
 #endif  // MOTORS_PRINT_ITM_