rust-cpython: drop manual management of mutably_borrowed
RefCell::borrow() should guarantee there's no mutable borrow.
As a follow up, maybe PySharedState can be a pure data structure + function.
Most ref-sharing business has already been moved to PySharedRef* and PyLeaked*.
[paths]
/ = /var/hg/repos/*
[web]
allow_push = *
push_ssl = False