GeezerVison

* origin/master: (1373 commits)
  bpo-1635741: Port mashal module to multi-phase init (python#22149)
  bpo-1635741: Port _string module to multi-phase init (pythonGH-22148)
  bpo-1635741: Convert _sha256 types to heap types (pythonGH-22134)
  bpo-1635741: Port the termios to multi-phase init (PEP 489) (pythonGH-22139)
  bpo-41732: add iterator to memoryview (pythonGH-22119)
  bpo-40744: Drop support for SQLite pre 3.7.3 (pythonGH-20909)
  bpo-41316: Make tarfile follow specs for FNAME (pythonGH-21511)
  bpo-41720: Add "return NotImplemented" in turtle.Vec2D.__rmul__(). (pythonGH-22092)
  bpo-1635741 port _curses_panel to multi-phase init (PEP 489) (pythonGH-21986)
  bpo-1635741: Port _overlapped module to multi-phase init (pythonGH-22051)
  bpo-1635741: Port _opcode module to multi-phase init (PEP 489) (pythonGH-22050)
  bpo-1635741 port zlib module to multi-phase init (pythonGH-21995)
  [doc] Add link to Generic in typing (pythonGH-22125)
  bpo-41513: Expand comments and add references for a better understanding (pythonGH-22123)
  bpo-1635741: Port _sha1, _sha512, _md5 to multiphase init (pythonGH-21818)
  closes bpo-41723: Fix an error in the py_compile documentation. (pythonGH-22110)
  [doc] Fix padding in some typing definitions (pythonGH-22114)
  Fix documented Python version for venv --upgrade-deps (pythonGH-22113)
  bpo-40318: Migrate to SQLite3 trace v2 API (pythonGH-19581)
  bpo-41687: Fix sendfile implementation to work with Solaris (python#22040)
  ...

Port the _string extension module to the multi-phase initialization
API (PEP 489).