This lets us use `next` or `prev` to decide whether to park the cursor
at the first or last filtered item.
Co-Authored-By: Nathan Sobo <nathan@zed.dev>
This required indexing UTF-16 positions in `Rope`. We tried opting
into the UTF-8 experimental support but it didn't seem to work
correctly and the standard is UTF-16 anyway.
Co-Authored-By: Nathan Sobo <nathan@zed.dev>