Fixed double hyphens that are rendered to literal en-dashes in the documenation.

Doc/library/_winreg.rst

-:mod:`_winreg` -- Windows registry access
-=========================================
+:mod:`_winreg` --- Windows registry access
+==========================================
 
 .. module:: _winreg
    :platform: Windows

Doc/library/importlib.rst

-:mod:`importlib` -- Convenience wrappers for :func:`__import__`
-===============================================================
+:mod:`importlib` --- Convenience wrappers for :func:`__import__`
+================================================================
 
 .. module:: importlib
    :synopsis: Convenience wrappers for __import__

Doc/library/msvcrt.rst

 
-:mod:`msvcrt` -- Useful routines from the MS VC++ runtime
-=========================================================
+:mod:`msvcrt` --- Useful routines from the MS VC++ runtime
+==========================================================
 
 .. module:: msvcrt
    :platform: Windows

Doc/tutorial/stdlib2.rst

 .. _tut-brieftourtwo:
 
 *********************************************
-Brief Tour of the Standard Library -- Part II
-*********************************************
+Brief Tour of the Standard Library --- Part II
+**********************************************
 
 This second tour covers more advanced modules that support professional
 programming needs.  These modules rarely occur in small scripts.