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/uart.h b/motors/print/uart.h
index 7d81577..e223ae7 100644
--- a/motors/print/uart.h
+++ b/motors/print/uart.h
@@ -4,8 +4,7 @@
 #include "motors/peripheral/uart.h"
 #include "motors/print/print.h"
 
-namespace frc971 {
-namespace motors {
+namespace frc971::motors {
 
 // A printing implementation using a hardware UART. This has a reasonably sized
 // buffer in memory and uses interrupts to keep the hardware busy. It could
@@ -28,7 +27,6 @@
 // Could easily create a subclass of UartPrinting that also implements
 // WriteDebug on a second UART, and conditionally instantiate that.
 
-}  // namespace motors
-}  // namespace frc971
+}  // namespace frc971::motors
 
 #endif  // MOTORS_PRINT_UART_H_