Distinguish between singleton and non-singleton workspace items

* Prompt to save singleton items before non-singleton ones
* Don't prompt to save multi-buffers if they contain excerpts to items that are open elsewhere and not being closed.

Co-authored-by: Nathan Sobo <nathan@zed.dev>
0becbe482aMax Brunsfeld committed on 5/23/2022, 11:03:00 PMparentfbd589b
6 files changedLine totals unavailable