Improve search url.

[StevenDufresne]

Copied from pattern directory.

function rewrite_urls() {
	// Redirect searches to `/search/term`.
	if ( is_search() && ! empty( $_GET['s'] ) ) {
		wp_redirect( home_url( '/search/' ) . urlencode( trim( get_query_var( 's' ) ) ) . '/' );
		exit();
	}
}

[ryelle]

This was necessary in the pattern directory because of the routing & SPA, I think. Is there a reason we need it for the showcase? SEO, maybe?

[StevenDufresne]

I can't remember exactly but the main site uses that pattern. We should probably maintain the consistency. I don't feel strongly though.

[ryelle]

I think that's also because the search page on that site needs to be the Search page for the google embed. In any case, consistency is good and I'm fine with establishing this as the way things should work.

The permalink https://wordpress.org/showcase-v2/search/vogue/ already works as a route, the issue here is redirecting /showcase/?s=term to /showcase/search/term/ — which is what the code above does.