Updated 4-arrays-loops

Added a note under the for loop section mentioning about skipping of different components of for loop.

2-js-basics/4-arrays-loops/README.md

@@ -77,6 +77,8 @@ The `for` loop requires 3 parts to iterate:
 - `condition` Expression that uses comparison operators to cause the loop to stop when `false`
 - `iteration-expression` Runs at the end of each iteration, typically used to change the counter value
 
+✅ Note: All the above mentioned three parts are optional you can skip any of them or all of them to get different results.
+  
 ```javascript
 // Counting up to 10
 for (let i = 0; i < 10; i++) {