Fix prefix/suffix calculation when determining copilot suggestion

Co-Authored-By: Nathan Sobo <nathan@zed.dev>
Co-Authored-By: Mikayla Maki <mikayla@zed.dev>
5f579a4287Antonio Scandurra committed on 3/31/2023, 4:05:07 PMparentb588ba1
3 files changedLine totals unavailable