svg spec links need to be updated.

https://github.com/search?q=repo%3Atobie%2Fspecref%20svgwg.org&type=code

Currently there are a couple of references to `svgwg.org` which makes in return bikeshed adds the wrong references in specs. 

The specs are now located at
https://w3c.github.io/svgwg/