Issue #29290: Merge 3.6.

diff --cc Misc/NEWS
index 6c2b43500f7e542f4516db0dd12f8157e30b6af7,c72755915e02ffb27bad95221ad6db26d14957b5..efd8e3263554f2c28737f6f01f2046ee6bdfc579
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -215,12 -47,13 +215,15 @@@ Core and Builtin
  Library
  -------
  
+ - Issue #29290: Fix a regression in argparse that help messages would wrap at
+   non-breaking spaces.
+ 
  - Issue #28735: Fixed the comparison of mock.MagickMock with mock.ANY.
  
 -- Issue #29316: Restore the provisional status of typing module, add
 -  corresponding note to documentation. Patch by Ivan L.
 +- Issue #29197: Removed deprecated function ntpath.splitunc().
 +
 +- Issue #29210: Removed support of deprecated argument "exclude" in
 +  tarfile.TarFile.add().
  
  - Issue #29219: Fixed infinite recursion in the repr of uninitialized
    ctypes.CDLL instances.