Append "Details" link to Nominatim search results

After using the OSM homepage search box to find some item (eg by the name of a business), it's very useful to be able to see the item's details - either to check whether editing is needed, or to read shop contact details, etc. This patch adds a simple "Details" link to Nominatim search results which makes it easy to get the info. (At present I use the "Browse map data" option, or just click "Edit", to see the details, but both of those are wasteful since they pull down much more data than one needs.)