Update notification banner to be flexible in what it accepts

[fofr]

The notification banner could include a variety of content. The API for this component should be as flexible as the design system's.

The following is not currently possible:

You are impersonating <a href="/">Paul Hayes</a> (email@email.com)

[Stop impersonating]

Suggestion:

• Add an html param, to pass in and render any provided html

Like:

{{ govukNotificationBanner({
  html: html
}) }}

https://design-system.service.gov.uk/components/notification-banner/

This is affecting this PR: DFE-Digital/get-help-with-tech#1410

[peteryates]

I think you should be able to do this now by passing in your content with a block:

<%= govuk_notification_banner(blah) do %>
  <h2>Inner content goes here</h2>
<% end %>

[fofr]

Ah, nice. Is there an example of this usage in the docs?

[peteryates]

Not exactly, I'll try to get it updated at some point - the whole docs could do with a re-jig.

[asmega]

oh yea i remember now sorry. I think i had this problem before and now going thru the same hoops due to my poor memory. to do the above we subclassed the component and override def render? to always return true. in our case we can't use the given heading as it doesn't fit our format. but in order for the component to render it must have a heading hence why we override this

[peteryates]

Ah! To be honest I think I added the render? method before thinking about allowing arbitrary content via blocks. I'll just remove it, can totally see why it's a pain in the rear 😅