_pyrepl: Add M-_ binding for yank-arg

Just like in readline, this does exactly the same thing as M-.

Author: L3viathan

Lib/_pyrepl/historical_reader.py

@@ -264,6 +264,7 @@ def collect_keymap(self) -> tuple[tuple[KeySpec, CommandName], ...]:
             (r"\C-s", "forward-history-isearch"),
             (r"\M-r", "restore-history"),
             (r"\M-.", "yank-arg"),
+            (r"\M-_", "yank-arg"),
             (r"\<page down>", "history-search-forward"),
             (r"\x1b[6~", "history-search-forward"),
             (r"\<page up>", "history-search-backward"),