Fixed code snippet syntax problem
Fixed code snippet syntax problem

By using curly quotation marks for the string in the code snippet some Markdown processors weren't able to close the string properly. GitHub was smart enough to handle this correctly but it was causing problems on the Package Control site.

I also switched the language from 'js' to 'json'
natecavanaugh/GitGutter,michaelhogg/GitGutter,akpersad/GitGutter,natecavanaugh/GitGutter,tushortz/GitGutter,michaelhogg/GitGutter,biodamasceno/GitGutter,biodamasceno/GitGutter,akpersad/GitGutter,akpersad/GitGutter,natecavanaugh/GitGutter,robfrawley/sublime-git-gutter,tushortz/GitGutter,biodamasceno/GitGutter,biodamasceno/GitGutter,jisaacks/GitGutter,michaelhogg/GitGutter,robfrawley/sublime-git-gutter,akpersad/GitGutter,robfrawley/sublime-git-gutter,tushortz/GitGutter,robfrawley/sublime-git-gutter,natecavanaugh/GitGutter,tushortz/GitGutter,michaelhogg/GitGutter