Class name consistency for woocommerce_attributes > product_attributes. See #4019
Fix markup on form-pay.php

Payment method fields were not displaying on the "Checkout -> Pay" page
because checkout.js was using a input#payment_method_{name} selector, which
worked fine with the payment method markup used in the review-order.php template,
but not with the markup used in the form-pay.php template.

This moves the #payment_method_{name} attribute from the <li/> elements to the
<input/> element so that checkout.js correctly display's payment method fields.
Merge pull request #4045 from scottbasgaard/master

Class name consistency for woocommerce_attributes > product_attributes. ...
Merge pull request #4047 from thenbrent/form_pay_fix

Fix markup on form-pay.php
Fixed docblock return type, closes #4057
Fixed docs for enabled params (string, not bool), closes #4052
Schema: ProductID can now be SKU, added URL