FreeCodeCamp

'Regular Expressions'-waypoint improvements

* Remove unnecessary `i`-flag from tests and test messages,
  e.g. `/\s+/gi` => `/\s+/g`
* Remove dupliate backslashes from regex test messages,
  e.g. `/\\s+/g` => `/\s+/g`

The two backslashes were probably just an accident caused by how
multiple escapes are necessary with the current way tests are handled.
The `i`-flag was just unnecessary since its purpose is to ignore the
case of alphabetic characters.