Render `@example` JSDoc tag for constructor

[moreal]

Now, it doesn't render @example JSDoc tag for classes' constructors. When to run deno doc --html ./mod.ts && open docs/~/A.html with mod.ts file:

// mod.ts
export class A {
    /**
     * @example Creates an instance.
     * ```
     * new A();
     * ```
     */
    constructor() {}

    /**
     * @example Call a method.
     * ```
     * const a = new A();
     * a.method();
     * ```
     */
    method() {}
}

It can see A.prototype.method's example but it cannot see A.prototype.constructor's example.

No route for A.prototype.constructor

It can see A.prototype.method's example at docs/~/A.prototype.method.html