Route not found to be mentioned in fileServer.js

[Anuraag-CH]

Need to mention this line
"- For any other route not defined in the server return 404.Should return Route not found as text if route is not found."

instead of "- For any other route not defined in the server return 404."

It fails during test case otherwise.

[Anuraag-CH]

Update fileServer.js #20 is the pull request

[aliabbas34]

Description wasn't good. I hope they take care of it next time.