PreProcess

Handle common directives that can occur in a block of text:

:include: filename

Directives can be escaped by preceding them with a backslash.

RDoc plugin authors can register additional directives to be handled by using RDoc::Markup::PreProcess::register.

Any directive that is not built-in to RDoc (including those registered via plugins) will be stored in the metadata hash on the CodeObject the comment is attached to. See RDoc::Markup@Directives for the list of built-in directives.