Add explanation for incrementing count variable

Added comment explaining the increment operation on the count variable.

Author: cywong-dev

Sprint-1/1-key-exercises/1-count.js

@@ -4,3 +4,6 @@ count = count + 1;
 
 // Line 1 is a variable declaration, creating the count variable with an initial value of 0
 // Describe what line 3 is doing, in particular focus on what = is doing
+
+// [ChunYanWong] It is used to increse the value of the variable by 1
+