Let package author customize wildcard import identifier in usage block

[lucacasonato]

Example:

Right now it is always mod. It would be nice if this was customizable by the module author, so that it could say import * as oauth from "@panva/oauth4webapi".

I suggest we add a module level JSDoc tag for this: @wildcardident <ident>. You could then specify it with:

/**
 * This module does xyz.
 * 
 * @module
 * @wildcardident oauth
 */

export ...