Support AttributeProvider for Alerts Extension Title #426

Is your feature request related to a problem? Please describe.
When rendering the new alert extension it does not seems possible to add a style attribute to the individual p tags. This is needed to add inline styles for html emails rather than relying on the added markdown-alert-title class

Describe the solution you'd like
update the rendering so that the p tags flow through the AttributeProvider like the alert Node does. Or add new nodes for AlertTitle and AlertContent

Describe alternatives you've considered
Have not considered any other alternatives.

Additional context
This is for html from markdown that is being used in html emails which do much better with inlined style rather than css classes