encode search string special characters for url slug

Searching for a merchant on the home page does not encode the space character for more than one word:

search "the greatest bar" -> goes to route /the-greatest%20bar

Start at the home-page merchant search and trace how the entered merchant name becomes the route. Reproduce the search for "the greatest bar" and inspect the resulting URL handling for spaces and other special characters. Done means the generated merchant route is encoded as the issue expects without breaking normal searches.

Written by the indexing model from the issue text.