Fixes Exercises:Level 3 in 12_day_regular_expressions.md

Fixed an indentation issue that results in an unintended result.

12_Day_Regular_expressions/12_day_regular_expressions.md

@@ -501,6 +501,7 @@ distance = 12
   ```sh
     I am a teacher and I love teaching There is nothing as more rewarding as educating and empowering people I found teaching more interesting than any other jobs Does this motivate you to be a teacher
   ```
+ 
 2. Write a function which find the most frequent words. After cleaning, count three most frequent words in the string.
 
   ```js