added documents chapter to table of contents

Author: Shiye Shizhi

README.md

@@ -20,6 +20,7 @@ Python sample codes and documents about Autonomous vehicle control algorithm. In
     * [Perception](#perception)
         * [Rectangle fitting Detection](#rectangle-fitting-detection)
         * [Sensor's Extrinsic Parameters Estimation](#sensors-extrinsic-parameters-estimation)
+* [Documents](#documents)
 * [License](#license)
 * [Use Case](#use-case)
 * [Contribution](#contribution)