Edited Javascript Roadmaps Content (#2142)

* Edited Javascript Roadmaps Content

Added some content in arithmetic operators & arrow functions. Amended one file name as well.

* Reverted the File name

Just reverted the name of the file as it was breaking the build.

content/roadmaps/106-javascript/content/108-javascript-expressions-and-operators/102-arithmetic-operators.md

@@ -6,9 +6,12 @@ Arithmetic operators in JavaScript are as follows:
 - `+` (Addition)
 - `-` (Subtraction)
 - `*` (Multiplication)
-- `/` (Division)
-- `%` (Remainder)
 - `**` (Exponentiation)
+- `/` (Division)
+- `%` (Modulus i.e. Remainder)
+- `++` (Increment)
+- `++` (Decrement)
 
 <BadgeLink colorScheme='yellow' badgeText='Read' href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators#arithmetic_operators'>Arithmetic Operators - MDN</BadgeLink>
 <BadgeLink colorScheme='yellow' badgeText='Read' href='https://javascript.info/operators#maths'>Arithmetic Operators - JavaScript.info</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.w3schools.com/js/js_arithmetic.asp'>JavaScript Arithmetic Operators</BadgeLink>

content/roadmaps/106-javascript/content/109-javascript-functions/102-arrow-functions.md

@@ -3,3 +3,4 @@
 Arrow Function is a new way of creating functions with the '=>' operator with a shorter syntax.
 
 <BadgeLink colorScheme="yellow" badgeText="Read" href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions">Arrow function expressions</BadgeLink>
+<BadgeLink colorScheme="yellow" badgeText="Read" href="https://www.w3schools.com/js/js_arrow_function.asp">JavaScript Arrow Function</BadgeLink>