Add typescript classes guide. (#26244)

* Add typescript classes guide.

* Fixed misspelled word.

* Made changes according to review comments

* Added output and rephrased sentence

guide/english/typescript/classes/index.md

@@ -0,0 +1,42 @@
+---
+title: Classes
+---
+
+# Classes
+
+Object Oriented Programming is an important programming principle, especially where a lot of code is written. By structuring the code in classes and objects, it makes the code easier to understand.
+Class is one of the paradigm of `OOP`.
+
+TypeScript uses the `class` keyword to create a class, like so - 
+
+```typescript
+class <class_name> {
+      // Fields 
+      
+      // Constructors
+      
+      // Functions
+      }
+```
+Class can embrace fields, constructors and functions in it.
+
+```typescript
+class Pet {  
+   name:string; 
+ 
+   constructor(name:string) { 
+      this.name = name;
+   }  
+
+   function show():void { 
+      console.log("Pet name is : " + this.name); 
+   } 
+}
+```
+To access the attributes of class `Pet`, It needs to create an instance of the class like under the hood -
+
+```typescript
+let pet = new Pet('Bruno');
+
+pet.show(); // Pet name is: Bruno
+```