bpo-35887: Add make regen-importlib step to importlib docs by nnja · Pull Request #11777 · python/cpython

@nnja

`make regen-importlib` needs to be run in order to regenerate
the the frozen version of the importlib module from _bootstrap.py.
The docstring has been updated to reflect that. Note that the same
instructions are in the _bootstrap_external.py docstring.

remilapeyre

brettcannon