"ES2018 rest/spread properties are not supported in Chrome 10, Firefox 11"
But... is it really useful to know that? The outcome regardless is that you can't use the feature. And you can always look it up on MDN yourself. So it might not be worth complicating the plugin with this.
Instead of
"ES2018 rest/spread properties are forbidden."
say
"ES2018 rest/spread properties are not supported in Chrome 10, Firefox 11"
But... is it really useful to know that? The outcome regardless is that you can't use the feature. And you can always look it up on MDN yourself. So it might not be worth complicating the plugin with this.