Use new multibuffer excerpts in project search (#27893)

Follow-up of https://github.com/zed-industries/zed/pull/27876
Closes https://github.com/zed-industries/zed/issues/13513

Release Notes:

- Improved multi buffer excerpts to merge when expanded

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/project/src/search.rs

@@ -15,6 +15,7 @@ use std::{
 use text::Anchor;
 use util::paths::PathMatcher;
 
+#[derive(Debug)]
 pub enum SearchResult {
     Buffer {
         buffer: Entity<Buffer>,