Fix vim code working on display map chars (#10103)

Release Notes:

- vim: Fixed motion bugs when softwrap, folds or inlay hints were used.

crates/multi_buffer/src/anchor.rs

@@ -137,3 +137,6 @@ impl AnchorRangeExt for Range<Anchor> {
         self.start.to_point(content)..self.end.to_point(content)
     }
 }
+
+#[derive(Clone, Copy, Eq, PartialEq, Debug, Hash, Ord, PartialOrd)]
+pub struct Offset(pub usize);