Including missing validation check

The validation check was removed from the update to the CommentForm handleSubmit function.
Adding `e.preventDefault()` to `handleSubmit`, 

Also added plain `return`, updated text.
Merge pull request #2078 from michaelrp/patch-1

Including missing validation check
[Docs] Make retina react logo work

Bourbon now takes *_2x instead of *@2x.
Merge pull request #2083 from chenglou/docs-retina-icon

[Docs] Make retina react logo work
Make the TapEvent plugin injectable