[11.x] Pick up existing views and markdowns when creating mails

[kevinb1989]

I spend a whole afternoon designing an email template named resources/views/customers/welcome.blade.php.

Then I run the command php artisan make:mail --view=customers.welcome.

And my completed template has been replaced with the stub file.

This is not exactly ideal, and it is easy to fix. People might have existing templates to use, or design them first. If blade files are already present, it would be great if they are picked up.

To be consistent, I do the same with markdowns.

[taylorotwell]

I would just return an error message that the file already exists.

[kevinb1989]

@taylorotwell No problem, I have updated according to your comment.

[kevinb1989]

@taylorotwell thanks boss! We plan to refactor our emails to mailables using existing blade files. This will make our lives way easier!