ms-dlx: fall back to BasicSearch
[MS-DLX] ChangeSearch functionality is extremely limited, as it only
finds exact matches.
But if the user enters only one search string we can improve the
experience by retrying with BasicSearch/BeginsWith. It will match that
one string against multiple fields. This will return more matches than
the user expects, but it is way better than no matches at all.
BasicSearch has been suggested in several threads. But IMHO the proposed
changes were all flawed compared to the implementation I have chosen
now.