Add json.scanner.NUMBER_RE (#13405)

Co-authored-by: Jelle Zijlstra <[email protected]>

Author: tjkuson

Diff for: stdlib/json/scanner.pyi

@@ -1,3 +1,7 @@
 from _json import make_scanner as make_scanner
+from re import Pattern
+from typing import Final
 
 __all__ = ["make_scanner"]
+
+NUMBER_RE: Final[Pattern[str]]  # undocumented