changed

I changed 'javascript' in 'js'

snippets/collatz.md

@@ -3,7 +3,7 @@
 If n even then returns **n/2** otherwise (n is odd) **3n+1**.
 It uses the ternary operator.
 
-``` javascript
+``` js
     const collatz = n => (n % 2 == 0) ? (n/2) : (3*n+1); 
     // collatz(8) --> 4
     // collatz(5) --> 16