Add private unparse names to getattr

Author: AA-Turner

Lib/ast.py

@@ -659,4 +659,10 @@ def __getattr__(name):
         from _ast_unparse import unparse
         return unparse
 
+    if name in {'_INFSTR', '_SINGLE_QUOTES', '_MULTI_QUOTES', '_ALL_QUOTES',
+                '_Precedence', '_Unparser'}:
+        # all of these names are private, but re-exported for compatibility
+        import _ast_unparse
+        return getattr(_ast_unparse, name)
+
     raise AttributeError(f'module {__name__!r} has no attribute {name!r}')