Let alpha go to 1 exactly

We were aborting on some splines when evaluating the end point.  Whops.

Change-Id: I10c59875ade7e66071e6451451aace12b9d8429a
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/y2023/control_loops/superstructure/arm/trajectory.cc b/y2023/control_loops/superstructure/arm/trajectory.cc
index 565f497..717a29e 100644
--- a/y2023/control_loops/superstructure/arm/trajectory.cc
+++ b/y2023/control_loops/superstructure/arm/trajectory.cc
@@ -155,7 +155,7 @@
                            distance_step_size +
                        static_cast<double>(before) * distance_step_size;
   CHECK_GT(alpha, 0.0);
-  CHECK_LT(alpha, 1.0);
+  CHECK_LE(alpha, 1.0);
   return alpha;
 }