For dubious reasons, ldoc uses the human readable name for the URLs
instead of the machine readable one. If the name has multiple words,
this causes the URLs to have spaces or %20 in them.
This commits remove all spaces from the "kinds" and then use `:gsub()`
in the template to convert underscores to spaces.
**WARNING** This breaks all URLs again. But this is necessary to prevent
broken links when the user paste them with spaces instead of %20.
Rather that abusing of how the arguments are displayed to convey the
type, add native support.
It still uses the @param for the doc, so this doesn't cause a million
little noisy changes, but the rendered HTML now have a real section for
the type. This is added to both the summary and the expanded description.
Additionally, if the type has a description string, a second is added.
Emmanuel Lepage Vallee
Daniel Hahler