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/frc971/vision/ceres/pose_graph_3d_error_term.h b/frc971/vision/ceres/pose_graph_3d_error_term.h
index 4dd5fbd..217b2a9 100644
--- a/frc971/vision/ceres/pose_graph_3d_error_term.h
+++ b/frc971/vision/ceres/pose_graph_3d_error_term.h
@@ -36,8 +36,7 @@
 
 #include "types.h"
 
-namespace ceres {
-namespace examples {
+namespace ceres::examples {
 
 // Computes the error term for two poses that have a relative pose measurement
 // between them. Let the hat variables be the measurement. We have two poses x_a
@@ -133,7 +132,6 @@
   const double weight_;
 };
 
-}  // namespace examples
-}  // namespace ceres
+}  // namespace ceres::examples
 
 #endif  // EXAMPLES_CERES_POSE_GRAPH_3D_ERROR_TERM_H_
diff --git a/frc971/vision/ceres/read_g2o.h b/frc971/vision/ceres/read_g2o.h
index 69fa16a..c427939 100644
--- a/frc971/vision/ceres/read_g2o.h
+++ b/frc971/vision/ceres/read_g2o.h
@@ -38,8 +38,7 @@
 
 #include "glog/logging.h"
 
-namespace ceres {
-namespace examples {
+namespace ceres::examples {
 
 // Reads a single pose from the input and inserts it into the map. Returns false
 // if there is a duplicate entry.
@@ -136,7 +135,6 @@
   return true;
 }
 
-}  // namespace examples
-}  // namespace ceres
+}  // namespace ceres::examples
 
 #endif  // EXAMPLES_CERES_READ_G2O_H_
diff --git a/frc971/vision/ceres/types.h b/frc971/vision/ceres/types.h
index 17e9bd3..9c1e495 100644
--- a/frc971/vision/ceres/types.h
+++ b/frc971/vision/ceres/types.h
@@ -39,8 +39,7 @@
 #include "Eigen/Core"
 #include "Eigen/Geometry"
 
-namespace ceres {
-namespace examples {
+namespace ceres::examples {
 
 struct Pose3d {
   Eigen::Vector3d p;
@@ -104,7 +103,6 @@
 typedef std::vector<Constraint3d, Eigen::aligned_allocator<Constraint3d>>
     VectorOfConstraints;
 
-}  // namespace examples
-}  // namespace ceres
+}  // namespace ceres::examples
 
 #endif  // EXAMPLES_CERES_TYPES_H_