Basic side-by-side diff implementation (#43586)

Release Notes:

- N/A

---------

Co-authored-by: cameron <cameron.studdstreet@gmail.com>
Co-authored-by: Cameron <cameron@zed.dev>

crates/editor/src/display_map/wrap_map.rs

@@ -1056,6 +1056,7 @@ impl Iterator for WrapRows<'_> {
             RowInfo {
                 buffer_id: None,
                 buffer_row: None,
+                base_text_row: None,
                 multibuffer_row: None,
                 diff_status,
                 expand_info: None,