Blockquote levels

[compunode]

The blockquote render is usually more than sufficient for the general use-case:

SundownRenderBase::blockQuote(string $quote)

However, it is missing some vital information regarding the blockquote level. For example it might be desirable to render each of the following differently:

> Level 1
>> Level 2
>>> Level 3

Would it be possible to extend the function signature to:

SundownRenderBase::blockQuote(string $quote, int $blockquote_level)

Making it optional will still not break backward compatibility while exposing this for use.