DDoc section styling, special casing

[kiith-sa]

Add a class for the

of each DDoc section based on its name (e.g. "params", "returns", "throws").

Will allow more customizable style. Maybe change around the default style, e.g. for Bugs:

Use some section names like Sphinx uses admonitions; we already use Note: in this way.

(Optional) allow DDoc sections in Params: by recursively parsing the parameter description.