Support for Quarto Callout Blocks

[dmetivie]

Following #267 I implemented (basically copying your code) support for callout quarto blocks. I added a test (hope it works, as I add plenty of weird message trying to run it).

I tried to add in the regex a function for detecting if there is a collapse="true" but could not get it work (I am not good at regex).

[dmetivie]

I noticed a bug. If there is a space after the name of the block, the regex won't detect the block e.g.

!!! warning 
    This won't be detected (of course no one see the space after warning but it is here!)