[5.3] Update policy.stub

[cracki]

fix doc block for namespaced model

[taylorotwell]

This PR doesn't describe what is broken. So I have no idea what to verify.

[cracki]

when using console command to generate policy, if model get namespaced (Ex. Model\Post) , generated doc block must use same name spaced path

[taylorotwell]

Please give me an exact Artisan command I can paste in my terminal to recreate the issue.

[cracki]

php artisan make:model Models\Mymodel
Model created successfully.

php artisan make:policy MymodelPolicy --model=Models\Mymodel
Policy created successfully.

---

generated doc block:

    /**
     * Determine whether the user can view the mymodel.
     *
     * @param  \App\User  $user
     * @param  \App\Mymodel  $mymodel
     * @return mixed
     */

this is correct:

     * @param  \App\Models\Mymodel  $mymodel