Add names to using parameters for cleaner docs

[nicolasstucki]

No description provided.

[odersky]

I am not sure this is a good idea. These names are just noise. What is the problem with the docs if they are left out? Maybe we need to upgrade the doc tool to handle this gracefully?

[nicolasstucki]

There are two issues

• All names appear as x$i
• We cannot refer to names in the @param in the docs

[arturopala]

What about adding @using annotation to the docs, accepting type name rather than parameter name? This would help to understand better the definition.

[nicolasstucki]

I will create an issue for this.