Improvement: Explorer Search is misleading when clicking "enter"

[achowdhry-ripple]

Right now, a user has to manually click the token search result they want to navigate to. Clicking Enter takes them to a broken link, since the search bar content is populated in the URL instead of the first search result's address.

Solution -- Add a highlight indicator by default to the first search result. If there is a search result (at least one), clicking enter will navigate to the correct path to the first one.