* origin/master: (27 commits)
  bpo-41428: Fix compiler warnings in unionobject.c (pythonGH-22388)
  bpo-41654: Fix compiler warning in MemoryError_dealloc() (pythonGH-22387)
  bpo-41833: threading.Thread now uses the target name (pythonGH-22357)
  bpo-30155: Add macros to get tzinfo from datetime instances (pythonGH-21633)
  bpo-33822: Update IDLE section of What's New 3.8 (pythonGH-22383)
  bpo-41844: Add IDLE section to What's New 3.9 (GN-22382)
  bpo-41841: Prepare IDLE News for 3.10 (pythonGH-22379)
  bpo-37779 : Add information about the overriding behavior of ConfigParser.read (pythonGH-15177)
  bpo-40170: Use inline _PyType_HasFeature() function (pythonGH-22375)
  bpo-40941: Fix stackdepth compiler warnings (pythonGH-22377)
  bpo-40941: Fix fold_tuple_on_constants() compiler warnings (pythonGH-22378)
  bpo-40521: Fix PyUnicode_InternInPlace() (pythonGH-22376)
  bpo-41834: Remove _Py_CheckRecursionLimit variable (pythonGH-22359)
  bpo-1635741, unicodedata: add ucd_type parameter to UCD_Check() macro (pythonGH-22328)
  bpo-1635741: Port _lsprof extension to multi-phase init (PEP 489) (pythonGH-22220)
  bpo-41513: Improve order of adding fractional values. Improve variable names. (pythonGH-22368)
  bpo-41816: `StrEnum.__str__` is `str.__str__` (pythonGH-22362)
  bpo-35764: Rewrite the IDLE Calltips doc section  (pythonGH-22363)
  bpo-41810: Reintroduce `types.EllipsisType`, `.NoneType` & `.NotImplementedType` (pythonGH-22336)
  bpo-41602: raise SIGINT exit code on KeyboardInterrupt from pymain_run_module (python#21956)
  ...

Remove the global _Py_CheckRecursionLimit variable: it has been
replaced by ceval.recursion_limit of the PyInterpreterState
structure.

There is no need to keep the variable for the stable ABI, since
Py_EnterRecursiveCall() and Py_LeaveRecursiveCall() were not usable
in Python 3.8 and older: these macros accessed PyThreadState members,
whereas the PyThreadState structure is opaque in the limited C API.