Simple docs cleanup (#1168)
Simple docs cleanup (#1168)

* Remove reference to format_int_string in docs

The function got dropped in 250ba7f04b300df284ba80cd4bb4122b45b41efb.

* Remove reference to is_python36 in docs

The function got removed in 36d3c516d3c09fc5f05c420900dd6b854e3c8bbd.

psf/black