Add typecasting docs (#1570)

* Update 103-javascript-type-casting

* Add typecasting docs

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/106-javascript/content/103-javascript-type-casting/readme.md

@@ -1 +1,7 @@
-# Javascript type casting
+# Type Casting
+
+Type conversion (or typecasting) means the transfer of data from one data type to another. Implicit conversion happens when the compiler (for compiled languages) or runtime (for script languages like [JavaScript](https://developer.mozilla.org/en-US/docs/Glossary/JavaScript)) automatically converts data types. The source code can also explicitly require a conversion to take place.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://javascript.info/type-conversions'>Type Conversions</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.w3schools.com/js/js_type_conversion.asp'>JavaScript Type Conversion</BadgeLink>