This was done to reduce the number of direct dependencies we have. It
should be functionally equivalent. The bundle size should not change,
as we use `clone` as a transitive dependency in a number of places.
* Specify type before parameter name
Various JSDoc `@param` entries were specified as `name {type}` rather
than `{type} name`.
A couple of `@return` entries have been given types as well.
* Use JSDoc optional syntax rather than Closure syntax
* Use @returns rather than @return
* Use consistent built-in type capitalization
Primitive types are lower-case, and Object is upper-case.
* Separate param/return description with a dash
