Minor fixes to generate_emoji_name_data.
Minor fixes to generate_emoji_name_data.

- Valid JSON doesn't allow a trailing comma in a list.
- Zacky wants the file name to be 'data.json', provided this as a
  default (in a subdir named 'emoji')

moyogo/nototools,googlefonts/nototools,anthrotype/nototools,googlefonts/nototools,googlefonts/nototools,anthrotype/nototools,dougfelt/nototools,googlei18n/nototools,moyogo/nototools,anthrotype/nototools,googlefonts/nototools,dougfelt/nototools,dougfelt/nototools,googlei18n/nototools,googlefonts/nototools,googlei18n/nototools,moyogo/nototools