gh-161039: fix detection of less >= 706 in _pyrepl/pager.py

Since less tag v706¹, less exits with a failure status when no filename
is provided.  Pass the `-?` option and redirect both stdout and stderr
to /dev/null.

Failure to detect `less` results in using `more` for users who don't
have MANPAGER or PAGER set, which is unexpected.

¹ gwsw/less@7c85230 (Exit with a failure
  status in more cases, 2026-06-14)

Author: tmzullinger

Lib/_pyrepl/pager.py

@@ -36,7 +36,7 @@ def get_pager() -> Pager:
         return lambda text, title='': tempfile_pager(plain(text), 'more <')
     if hasattr(os, 'system') and os.system('(pager) 2>/dev/null') == 0:
         return lambda text, title='': pipe_pager(text, 'pager', title)
-    if hasattr(os, 'system') and os.system('(less) 2>/dev/null') == 0:
+    if hasattr(os, 'system') and os.system('(less -?) >/dev/null 2>&1') == 0:
         return lambda text, title='': pipe_pager(text, 'less', title)
 
     import tempfile