feat(Timeline/TrendingLink): provide WebURL

Since the Web version now has a user-visible timeline, we can provide a
URL to that.

mastodon/src/main/java/org/joinmastodon/android/fragments/discover/DiscoverTrendingLinkTimelineFragment.java

@@ -131,8 +131,7 @@ public class DiscoverTrendingLinkTimelineFragment extends StatusListFragment{
 
 	@Override
 	public Uri getWebUri(Uri.Builder base) {
-		//TODO: add URL link once web version implements a UI
-		return base.path("/explore/links").build();
+		return base.path("/links").appendPath(trendingLink.url).build();
 	}
 
 	@Override