vim: Handle exclusive-linewise edgecase correctly (#27786)

Before this change we didn't explicitly handle vim's exclusive-linewise
edgecase
(https://neovim.io/doc/user/motion.html#exclusive).

Instead we had hard-coded workarounds in a few places to make our tests
pass.
The most pernicious of these workarounds was that we represented a
visual line
selection as including the trailing newline (or leading newline for
files that
end with no newline), which other code had to undo to get back to what
the user
indended.

Closes #21440
Updates #6900

Release Notes:

- vim: Fixed `d]}` to not delete the closing brace
- vim: Fixed `d}` from the start of the line to not delete the paragraph
separator
- vim: Fixed `d}` from the middle of the line to not delete the final
newline

crates/editor/src/display_map.rs

@@ -752,27 +752,11 @@ impl DisplaySnapshot {
 
     // used by line_mode selections and tries to match vim behavior
     pub fn expand_to_line(&self, range: Range<Point>) -> Range<Point> {
-        let max_row = self.buffer_snapshot.max_row().0;
-        let new_start = if range.start.row == 0 {
-            MultiBufferPoint::new(0, 0)
-        } else if range.start.row == max_row || (range.end.column > 0 && range.end.row == max_row) {
-            MultiBufferPoint::new(
-                range.start.row - 1,
-                self.buffer_snapshot
-                    .line_len(MultiBufferRow(range.start.row - 1)),
-            )
-        } else {
-            self.prev_line_boundary(range.start).0
-        };
-
-        let new_end = if range.end.column == 0 {
-            range.end
-        } else if range.end.row < max_row {
-            self.buffer_snapshot
-                .clip_point(MultiBufferPoint::new(range.end.row + 1, 0), Bias::Left)
-        } else {
-            self.buffer_snapshot.max_point()
-        };
+        let new_start = MultiBufferPoint::new(range.start.row, 0);
+        let new_end = MultiBufferPoint::new(
+            range.end.row,
+            self.buffer_snapshot.line_len(MultiBufferRow(range.end.row)),
+        );
 
         new_start..new_end
     }