Change end of file style to single newline.

I'd like to change to a single `\n` at the end of the file. To my knowledge the typical approach is a single newline at EOF (this is what git will complain about if missing). This is what [C does](http://gcc.gnu.org/ml/gcc/2003-11/msg01568.html).

Any idea why AirBnb's style guide specifies an extra newline? Is there a functional reason?

I didn't catch this before because I interpreted the sentence as what I wanted to read. ;)