Fixes to template files that were causing validation errors.

1. templates/myaccount/my-orders.php
The <time> contents weren't valid time format, so I added a datetime property.

2. templates/single-product/add-to-cart/quantity.php
size isn't valid on <input> of type "number".

3. templates/single-product/review.php
There was a duplicate 'time' in there.