update README

Author: AtsushiSakai

README.md

@@ -158,15 +158,15 @@ Ref:
 
 This is a Extended Kalman Filter based SLAM example.
 
-The blue line is ground truth, the black line is dead reckoning, the red line is estimated trajectory with EKF SLAM.
+The blue line is ground truth, the black line is dead reckoning, the red line is the estimated trajectory with EKF SLAM.
 
 The green cross are estimated landmarks.
 
 ![3](https://github.com/AtsushiSakai/PythonRobotics/blob/master/SLAM/EKFSLAM/animation.gif)
 
 Ref:
 
-- [PROBABILISTIC\-ROBOTICS\.ORG](http://www.probabilistic-robotics.org/)
+- [PROBABILISTIC ROBOTICS](http://www.probabilistic-robotics.org/)
 
 # Path Planning