Add an option to ignore symbolic links when fuzzy finding

[semin-park]

I haven't thought through what exactly needs to change, but it would be nice to add a configuration option to let the fuzzy finder ignore symbolic links.

This will be useful when the user is working in a large codebase and has a lot of symbolic links for whatever reason. For example, I was working on a codebase with a lot of symlinks generated during compilation, and helix was showing 900,000 files including symbolic links whereas there were only(?) 350,000 real files in the directory.

Since helix fuzzy finder is currently synchronous, being able to ignore symlinks will also provide a nice side effect of snappier results.