(Merge 3.4) Issue #21155: asyncio.EventLoop.create_unix_server() now raises a

ValueError if path and sock are specified at the same time. asyncio: Document
Task.cancel() properly.

diff --cc Misc/NEWS
index 3bc36a9b5b186f65c555080193359c8dac5a4b2f,ec4ea5cd4ec6432393d22c64c8dc1641ddde6d0e..a27eb51074e21ce11cddeccb3894c7332e9c0427
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -29,19 -27,9 +29,22 @@@ Core and Builtin
  Library
  -------
  
+ - Issue #21155: asyncio.EventLoop.create_unix_server() now raises a ValueError
+   if path and sock are specified at the same time.
+ 
 +- Issue #21136: Avoid unnecessary normalization of Fractions resulting from
 +  power and other operations.  Patch by Raymond Hettinger.
 +
 +- Issue #17621: Introduce importlib.util.LazyLoader.
 +
 +- Issue #21076: signal module constants were turned into enums.
 +  Patch by Giampaolo Rodola'.
 +
 +- Issue #20636: Improved the repr of Tkinter widgets.
 +
 +- Issue #19505: The items, keys, and values views of OrderedDict now support
 +  reverse iteration using reversed().
 +
  - Issue #21149: Improved thread-safety in logging cleanup during interpreter
    shutdown. Thanks to Devin Jeanpierre for the patch.