Split the non-empty-title fail message

[WilcoFiers]

The non-empty-title failure message describes two states in one message:

Element has no title attribute or the title attribute is empty

It would be better if there were two separate messages:

Element has no title attribute
The title attribute is empty

This can be done using this.data({ messageKey }) in the evaluate method, and converting the fail message to an object. See checks/language/has-lang.json for an example.

[padmavemulapati]

if title is not defined or empty title - seperate messages should display
<img id="target" title=" " />' `

[straker]

No docs required