Adjust "spaces" when selecting a history item from search suggestions

Created by: quinnkeast

When selecting an item in the search history from the search suggestions, there's two quick changes that should improve usability:

• A leading space character is currently inserted before the query. This should be removed.
• Insert a space after the query. This will make it easier to immediately start building on the same query, and will prevent a second search suggestion from being shown immediately, such as in this screenshot:

/cc @benvenker @lguychard