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/frc971/control_loops/binomial.h b/frc971/control_loops/binomial.h
index 4f4c4dc..9ccc824 100644
--- a/frc971/control_loops/binomial.h
+++ b/frc971/control_loops/binomial.h
@@ -1,8 +1,7 @@
 #ifndef FRC971_CONTROL_LOOPS_BINOMIAL_H_
 #define FRC971_CONTROL_LOOPS_BINOMIAL_H_
 
-namespace frc971 {
-namespace control_loops {
+namespace frc971::control_loops {
 
 // Computes the factorial of n
 constexpr double Factorial(int n) {
@@ -18,7 +17,6 @@
   return Factorial(n) / (Factorial(k) * Factorial(n - k));
 }
 
-}  // namespace control_loops
-}  // namespace frc971
+}  // namespace frc971::control_loops
 
 #endif  // FRC971_CONTROL_LOOPS_BINOMIAL_H_