[gatsby-link] Export NavLink explicitly from the package

[kripod]

Instead of automatically choosing an appropriate React Router link component based on the given props, I think that letting developers explicitly choose NavLink over Link should be a possibility.

That approach would make styling Glamorous components much easier compared to the current approach:

const CustomLink = glamorous(({ ...props }) => <Link exact {...props} />)({
  // CSS
});

[KyleAMathews]

Let's consider this for v2

[nsimonson]

Not really sure if it's better or worse for gatsby to have them split out, but FWIW you can set defaultProps on the glamorous component directly.

const CustomLink = glamorous(Link)({
  // CSS
  '.active': {
    // Active styles
  }
})

CustomLink.defaultProps = {
  exact: true
}

[KyleAMathews]

Not relevant now that we've moved to @reach/router.

[bebyx]

@KyleAMathews There's a lack of support for Reach Router's <NavLink> though.