Update `link` docs to have an accessibile `div` (#7063)
Update `link` docs to have an accessibile `div` (#7063)

I love that Gatsby has updated to use a router which manages focus for AT users! 🎉  When reading through the docs I noticed there's an example that puts an `onClick` handler on a plain `div`, which isn't accessibile. I've added a few props to the example so if people do choose to copy & paste it, they don't lose any accessibility (unless they don't implement the `onKeyUp` handler).

Thanks for all the work you all have put into this!
0x80/gatsby,mingaldrichgan/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,gatsbyjs/gatsby,fk/gatsby,gatsbyjs/gatsby,fk/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,fk/gatsby,0x80/gatsby