CriticMarkup implementation incomplete/incompatible
one of the features of Gollum is support for CriticMarkup. It seems that we support some variation of it here, e.g.
> {+ this is an addition +} and {- this is a removal -}
does:
this is an addition and this is a removal
This is different from the CriticMarkup format, which is supposed to be:
> {++ this is an addition ++} and {-- this is a removal --}
It also supports things like substitutions, highlights, and comments.