Added linting, processed current snippets

snippets/average-of-array-of-numbers.md

@@ -3,7 +3,6 @@
 Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`, divide by the `length` of the array.
 
 ```js
-const average = arr =>
-  arr.reduce( (acc , val) => acc + val, 0) / arr.length;
+const average = arr => arr.reduce((acc, val) => acc + val, 0) / arr.length;
 // average([1,2,3]) -> 2
 ```