Do not show non-existing locations as having been searched
Get rid of redundant mapping of a match in a pair

The pair’s first member (document) is also part of the match data.
Get rid of find::scan_path_matches_t typdef

This is (now) just a std::vector of find::match_t records.
Fix range exception
Skip setting (complex) window title when we have no document name

Incase there is no window title settings key then we will set the window title to nil, which throws an exception.