Missing trailing newline

[cthoyt]

Line 170 of nbstripout.py reads as f.write('\n*.ipynb filter=nbstripout'). With the context manager on line 169, this appends the filter to .gitattributes without a trailing new line character.

This might be a matter of opinion, but it would be nice to have a trailing new character, especially because this line is being appended to the end of the file. Also, since the script includes from __future__ import print_function, this line could be rewritten as print('\n*.ipynb filter=nbstripout', file=f) to accomplish this.

[kynan]

Good suggestion, I'll implement that!