Consider that qf#GetEntryPath might return an empty string

[LemonBoy]

s:JumpFileChunk should be aware of this and skip the line accordingly.

[ntnn]

Mhm.

Two ways we could go about this:

1. Additional logic in qf#GetEntryPath to waltz up the entries until
   it found a path.
   That would work but then we'll need error handling in the calling
   functions, in case e.g. the first few lines have now paths.

2. Add additional logic in qf#preview#PreviewFileUnderCursor and
   s:JumpFileChunk to act accordingly.

Imho the first option would be more error prone, especially in the long run.

What do you think, @romainl?

[ntnn]

Afterthought - the best thing would be a wrapper qf#GetEntryPathRecursive(o.s.) around qf#GetEntryPath, which does go until the first available and returns nil if none was found.