runners/recentddocuments: match only inside file names

So that query "a" would only match "a/" or "a.txt", but not "a/b.txt". It doesn't make a lot of sense imo to recursively list all recently used files of a directory rather than just the matching directory itself.

Alternative 1: Include these matches, but with lower relevance.

Alternative 2: Instead return the matching parent directory, i.e. "a" in the example of "a/b.txt".