This is simply false AFAICS. There was little participation on this particular issue during PEP 374 that I can recall. Now that it is clearly an issue after all, it's still early in the PEP 385 process. Martin has already picked up the ball on EOL support, and has carried informal design pretty much to the goal line already ... all that's left is the detailed design and the implementation, and there are several people involved who will help develop the patch, all very capable.
I'm not so optimistic. To me, it looks like that either Dirkjan or Mark will implement a hg hook, or else it won't happen (for me, I certainly know that I will not write Mercurial hooks anytime soon).