Merge pull request #492 from Nirma/fix_contributing

Fixed typo in CONTRIBUTING.md

CONTRIBUTING.md

@@ -27,7 +27,7 @@ If your plugin is complex, make sure to include tests, we suggest using [fish-sp
 
 ### Themes
 
-Make sure to include a screenshot in your pull request, but don't commit the file to git. A nifty way is too post a comment with the image and link directly to it.
+Make sure to include a screenshot in your pull request, but don't commit the file to git. A nifty way is to post a comment with the image and link directly to it.
 
 
 [pr]: https://github.com/oh-my-fish/oh-my-fish/compare/