Fixed checkboxes.

Author: John Washam

README.md

@@ -249,8 +249,8 @@ Sometimes the classes are not in session so you have to wait a couple of months,
     - [ ] [Gayle L McDowell - Cracking The Coding Interview (video)](https://www.youtube.com/watch?v=rEJzOhC5ZtQ)
     - [ ] [Cracking the Coding Interview with Author Gayle Laakmann McDowell (video)](https://www.youtube.com/watch?v=aClxtDcdpsQ)
 - [ ] Cracking the Facebook Coding Interview
-    - [] [The Approach](https://www.youtube.com/watch?v=wCl9kvQGHPI)
-    - [] [Problem Walkthrough](https://www.youtube.com/watch?v=4UWDyJq8jZg)
+    - [ ] [The Approach](https://www.youtube.com/watch?v=wCl9kvQGHPI)
+    - [ ] [Problem Walkthrough](https://www.youtube.com/watch?v=4UWDyJq8jZg)
 - [ ] Prep Course:
     - [ ] [Software Engineer Interview Unleashed (paid course)](https://www.udemy.com/software-engineer-interview-unleashed):
         - Learn how to make yourself ready for software engineer interviews from a former Google interviewer.