Fix the Product URL (?)

[bupp925]

https://github.com/SearchSpring/magento2-searchspring-feed/blob/master/Helper/Generator.php#L188

I'm having a hard time understanding why the "url" field doesn't always work; in setups past, I've seen several of these URLs go to 404 pages. You'd know why that is better than I would, but seems like this "url" field should be updated to just reference domain.com/%url_key% instead? ... or something which always populated with a working URL.

For my understanding, this URL format can be configured differently for each store? Maybe there's a more reliable option than $product->getProductUrl()

Would be good if we could just use "url" as our Core Field, instead of remembering that a custom format is needed.