minor: Remove title colon

[vincentmorneau]

This is very minor, but I think the colon should not be there here https://github.com/brutusin/json-forms/blob/master/src/js/brutusin-json-forms.js#L1034

User can choose to add a colon in his decorator.

[idelvall]

sure, can you create a PR?
if so, please also add a modification to the example index.html with a decorator adding the colons

Thanks

[vincentmorneau]

Will do in the coming days.