Updated snippets

Mainly for better readability

snippets/measure-time-taken-by-function.md

@@ -4,8 +4,8 @@ Use `performance.now()` to get start and end time for the function, `console.log
 First argument is the function name, subsequent arguments are passed to the function.
 
 ```js
-const timeTaken = (f,...args) => {
-  var t0 = performance.now(), r = f(...args);
+const timeTaken = (func,...args) => {
+  var t0 = performance.now(), r = func(...args);
   console.log(performance.now() - t0);
   return r;
 }