Add type parameters to rendered rst for functions, classes, and interfaces

[hoodmane]

When rendering a jsfunction, jsclass, or jsinterface, if there are type params include them. Like:

function f<S, T>(x, y)

I also removed the parens from classes and interfaces because they look weird.

We had to add an extra docutils node for js-type-params because the normal type params docutils node uses square brackets not angle brackets.