editor: Remove buffer and display map fields from SelectionsCollection (#42175)

Release Notes:

- N/A *or* Added/Fixed/Improved ...

crates/editor/src/display_map/block_map.rs

@@ -63,6 +63,14 @@ pub struct BlockSnapshot {
     pub(super) excerpt_header_height: u32,
 }
 
+impl Deref for BlockSnapshot {
+    type Target = WrapSnapshot;
+
+    fn deref(&self) -> &Self::Target {
+        &self.wrap_snapshot
+    }
+}
+
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct CustomBlockId(pub usize);
 

crates/editor/src/display_map/fold_map.rs

@@ -630,6 +630,14 @@ pub struct FoldSnapshot {
     pub version: usize,
 }
 
+impl Deref for FoldSnapshot {
+    type Target = InlaySnapshot;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inlay_snapshot
+    }
+}
+
 impl FoldSnapshot {
     pub fn buffer(&self) -> &MultiBufferSnapshot {
         &self.inlay_snapshot.buffer

crates/editor/src/display_map/inlay_map.rs

@@ -32,6 +32,14 @@ pub struct InlaySnapshot {
     pub version: usize,
 }
 
+impl std::ops::Deref for InlaySnapshot {
+    type Target = MultiBufferSnapshot;
+
+    fn deref(&self) -> &Self::Target {
+        &self.buffer
+    }
+}
+
 #[derive(Clone, Debug)]
 enum Transform {
     Isomorphic(TextSummary),

crates/editor/src/display_map/tab_map.rs

@@ -167,6 +167,14 @@ pub struct TabSnapshot {
     pub version: usize,
 }
 
+impl std::ops::Deref for TabSnapshot {
+    type Target = FoldSnapshot;
+
+    fn deref(&self) -> &Self::Target {
+        &self.fold_snapshot
+    }
+}
+
 impl TabSnapshot {
     pub fn buffer_snapshot(&self) -> &MultiBufferSnapshot {
         &self.fold_snapshot.inlay_snapshot.buffer

crates/editor/src/display_map/wrap_map.rs

@@ -43,6 +43,14 @@ pub struct WrapSnapshot {
     interpolated: bool,
 }
 
+impl std::ops::Deref for WrapSnapshot {
+    type Target = TabSnapshot;
+
+    fn deref(&self) -> &Self::Target {
+        &self.tab_snapshot
+    }
+}
+
 #[derive(Clone, Debug, Default, Eq, PartialEq)]
 struct Transform {
     summary: TransformSummary,