Update README.md

Author: MarcoZeee

README.md

@@ -136,7 +136,7 @@ Node.js runs in a single process and the application code runs in a single threa
 
 Just like JS, there are two categories of data types in Node: Primitives and Objects.
 
-*Primitive Types*
+*Primitives*
 
 * String
 * Number
@@ -146,14 +146,15 @@ Just like JS, there are two categories of data types in Node: Primitives and Obj
 * Null
 * Symbol
 
-* `Buffer`: Node.js includes an additional data type called Buffer (not available in browser\'s JavaScript). Buffer is mainly used to store binary data, while reading from a file or receiving packets over the network.
-
 *Objects* 
 
 * Function
 
 * Array
 
+* `Buffer`: Node.js includes an additional data type called Buffer (not available in browser\'s JavaScript). Buffer is mainly used to store binary data, while reading from a file or receiving packets over the network. `Buffer` is a class.
+
+
 * other regular objects