Rust 1.78 (#11314)

Notable things I've had to fix due to 1.78:
- Better detection of unused items
- New clippy lint (`assigning_clones`) that points out places where assignment operations with clone rhs could be replaced with more performant `clone_into`
Release Notes:

- N/A

crates/editor/src/display_map/fold_map.rs

@@ -6,7 +6,6 @@ use gpui::{ElementId, HighlightStyle, Hsla};
 use language::{Chunk, Edit, Point, TextSummary};
 use multi_buffer::{Anchor, AnchorRangeExt, MultiBufferSnapshot, ToOffset};
 use std::{
-    any::TypeId,
     cmp::{self, Ordering},
     iter,
     ops::{Add, AddAssign, Deref, DerefMut, Range, Sub},
@@ -1066,28 +1065,6 @@ impl<'a> Iterator for FoldChunks<'a> {
     }
 }
 
-#[derive(Copy, Clone, Eq, PartialEq)]
-struct HighlightEndpoint {
-    offset: InlayOffset,
-    is_start: bool,
-    tag: Option<TypeId>,
-    style: HighlightStyle,
-}
-
-impl PartialOrd for HighlightEndpoint {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
-impl Ord for HighlightEndpoint {
-    fn cmp(&self, other: &Self) -> Ordering {
-        self.offset
-            .cmp(&other.offset)
-            .then_with(|| other.is_start.cmp(&self.is_start))
-    }
-}
-
 #[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq)]
 pub struct FoldOffset(pub usize);