Improve function signature presentation in HTML

[awelzel]

After looking a bit at docs, I find the HTML Type: presentation of a function's type much too noisy/distracting/challenging for reading. It's also a bit unusual to have the name and prototype separated - may just collapse them. Mentioning function in the signature likely is redundant, too, because this is all in a section called "Functions".

I think with a bit of wrangling we might be able to include the types of parameters into the Parameters section and make them link/clickable there instead (could also allow for some validation that the docstring params align with the signature).

Comparison examples form other docs