fix: add clear_all method to console class

Author: sharmaigne

Lib/_pyrepl/console.py

@@ -114,6 +114,10 @@ def clear(self) -> None:
         """Wipe the screen"""
         ...
 
+    def clear_all(self) -> None:
+        """Clear screen and scrollback buffer."""
+        ...
+
     @abstractmethod
     def finish(self) -> None:
         """Move the cursor to the end of the display and otherwise get