Update README.md

Author: richard-elvira

README.md

@@ -209,6 +209,6 @@ Once ORB-SLAM3 has loaded the vocabulary, press space in the rosbag tab.
   rosrun rosbag fastrebag.py dataset-room1_512_16.bag dataset-room1_512_16_small_chunks.bag
   ```
 
-# 7. Time analysis
+# 7. Running time analysis
 A flag in `include\Config.h` activates time measurements. It is necessary to uncomment the line `#define REGISTER_TIMES` to obtain the time stats of one execution which is shown at the terminal and stored in a text file(`ExecTimeMean.txt`).