Update perception/radar_crossing_objects_noise_filter/README.md

Co-authored-by: Yoshi Ri <yoshiyoshidetteiu@gmail.com>

Author: scepter914

perception/radar_crossing_objects_noise_filter/README.md

@@ -71,7 +71,7 @@ To filter the objects crossing to ego vehicle, this package filter the objects a
   - Default parameter is 1.0472.
 
 This parameter is the angle threshold to filter. It has condition that 0 < `angle_threshold` < pi / 2. If the crossing angle is larger than this parameter, it can be a candidate for noise object. In other words, if it is smaller than this parameter, it is a filtered object.
-If this parameter is set smaller, more objects are considered noise. In detail. see algorithm chapter.
+If this parameter is set smaller, more objects are considered noise. In detail, see algorithm chapter.
 
 - `velocity_threshold` (double) [m/s]
   - Default parameter is 3.0.