Update JavaScript switch statement (#2161)

add syntax highlighting in code snippet.

content/roadmaps/106-javascript/content/107-javascript-control-flow/101-conditional-statements/101-switch.md

@@ -1,8 +1,9 @@
-# Switch
+# Switch Case
 
 The `switch` statement evaluates an expression, matching the expression's value against a series of `case` clauses, and executes statements after the first `case` clause with a matching value, until a `break` statement is encountered. The `default` clause of a `switch` statement will be jumped to if no `case` matches the expression's value.
 
-```
+## Example
+```js
 switch (expression) {
   case value1:
     //Statements executed when the result of expression matches value1
@@ -22,4 +23,4 @@ switch (expression) {
 
 <ResourceGroupTitle>Free Content</ResourceGroupTitle>
 <BadgeLink colorScheme='blue' badgeText='Read' href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/switch'>switch - MDN</BadgeLink>
-<BadgeLink colorScheme='blue' badgeText='Read' href='https://javascript.info/switch'>The switch statement</BadgeLink>
+<BadgeLink colorScheme='blue' badgeText='Read' href='https://javascript.info/switch'>The switch statement - javascript.info</BadgeLink>