Allow buffer search to search deleted hunks (#23632)

Closes #ISSUE

Release Notes:

- N/A

crates/multi_buffer/src/multi_buffer.rs

@@ -3376,6 +3376,49 @@ impl MultiBufferSnapshot {
         result
     }
 
+    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
+        &self,
+        range: Range<T>,
+    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
+        let start = range.start.to_offset(&self);
+        let end = range.end.to_offset(&self);
+
+        let mut cursor = self.cursor::<usize>();
+        cursor.seek(&start);
+
+        std::iter::from_fn(move || {
+            let region = cursor.region()?;
+            if region.range.start > end {
+                return None;
+            }
+            let start_overshoot = start.saturating_sub(region.range.start);
+            let end_overshoot = end.saturating_sub(region.range.start);
+            let start = region
+                .buffer_range
+                .end
+                .min(region.buffer_range.start + start_overshoot);
+            let end = region
+                .buffer_range
+                .end
+                .min(region.buffer_range.start + end_overshoot);
+
+            let region_excerpt_id = region.excerpt.id;
+            let deleted_hunk_anchor = if region.is_main_buffer {
+                None
+            } else {
+                Some(self.anchor_before(region.range.start))
+            };
+            let result = (
+                region.buffer,
+                start..end,
+                region_excerpt_id,
+                deleted_hunk_anchor,
+            );
+            cursor.next();
+            Some(result)
+        })
+    }
+
     /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
     /// coordinates.
     ///
@@ -4205,36 +4248,7 @@ impl MultiBufferSnapshot {
     where
         D: TextDimension + Ord + Sub<D, Output = D>,
     {
-        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
-        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
-
-        cursor.seek(locator, Bias::Left, &());
-        if cursor.item().is_none() {
-            cursor.next(&());
-        }
-
-        let mut excerpt_position = D::from_text_summary(&cursor.start().text);
-        if let Some(excerpt) = cursor.item() {
-            if excerpt.id == anchor.excerpt_id {
-                let excerpt_buffer_start =
-                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
-                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
-                let buffer_position = cmp::min(
-                    excerpt_buffer_end,
-                    anchor.text_anchor.summary::<D>(&excerpt.buffer),
-                );
-                if buffer_position > excerpt_buffer_start {
-                    excerpt_position.add_assign(&(buffer_position - excerpt_buffer_start));
-                }
-            }
-        }
-
-        let mut diff_transforms_cursor = self
-            .diff_transforms
-            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
-        diff_transforms_cursor.seek(&ExcerptDimension(excerpt_position), Bias::Left, &());
-
-        self.resolve_summary_for_anchor(anchor, excerpt_position, &mut diff_transforms_cursor)
+        self.summaries_for_anchors([anchor])[0]
     }
 
     fn resolve_summary_for_anchor<D>(