Latest versions of Sphinx (at least 3.1.0) do not need the `*` escaped and
will render the `\` in the output if it is there, so remove it.
Fixes issue #6209.
This commit adds Loop.new_event_loop() which is used to reset the singleton
event loop. This functionality is put here instead of in Loop.close() to
make it possible to write code that is compatible with CPython.
