Instead use keyword only arguments to os.register_at_fork for each of the scenarios.
Updates the documentation for clarity.

* bpo-16500: Allow registering at-fork handlers

* Address Serhiy's comments

* Add doc for new C API

* Add doc for new Python-facing function

* Add NEWS entry + doc nit

Issue 28475:  Improve error message for random.sample() with k < 0. (Contributed by Francisco Couzo).

Issue #27776: The os.urandom() function does now block on Linux 3.17 and newer
until the system urandom entropy pool is initialized to increase the security.

This change is part of the PEP 524.

to fully cover its state space.

- my previous removal and hg resolve mark had still left them and hooks did not catch it too!

Addresses issue #14927

error messages and comments.

Initial patch by Yuriy Senko.

We don't put coverage directives in the stdlib, but anyone looking at a
coverage report for Random should see the comment and understand why the lines
aren't covered.

Patch by Alessandro Moura.