Fix vi command invalidation

Author: lkollar

Lib/_pyrepl/vi_commands.py

@@ -416,8 +416,9 @@ def do(self) -> None:
         pending_char = self.event[-1]
         if not pending_char or r.pos >= len(r.buffer):
             return
+        pos = r.pos
         r.buffer[r.pos] = pending_char
-        r.dirty = True
+        r.invalidate_buffer(pos)
 
 class vi_replace_cancel(Command):
     """Cancel pending replace operation."""
@@ -440,4 +441,4 @@ def do(self) -> None:
         state = r.undo_stack.pop()
         r.buffer[:] = state.buffer_snapshot
         r.pos = state.pos_snapshot
-        r.dirty = True
+        r.invalidate_buffer(0)