Suggestion: new block definition to support <aside/>, <small/>

Hi,

Some HTML tags are not supported by asciidoctor right now. Example : <aside/>, <small> ... and most probably that they will not be processed in a future version. Nevertheless, the end user could be interested to tell to asciidoctor that such HTML tags should be added to the HTML generated. Until now, we can include text which is not processed using the syntax '+++ TEXT  +++'

Example

+++<aside class="notes">+++
Oh hey, these are some notes.
+++</aside>+++

What I would to suggest is that we add new options to the block definition

Current definition :

[role=aRole, style=aStyle, key=value, key=value]

Question : What is goal of the Role at the beginning of the block ?

New Definition

[role=aRole, tag=aTag, class=aCssClass, key=value, key=value]
where :
- aTag could be aside, small, ... (optional)
- class corresponds to a CSS Class of the stylesheet (optional)

Example

[tag=aside,class=notes]
Oh hey, these are some notes.

Render like that in HTML
<aside class="notes">
Oh hey, these are some notes.
</aside>

Regards,

Charles