[3.6] bpo-33943: Add references in the docs for logging.basicConfig (GH-7858) by miss-islington · Pull Request #7899

[3.6] bpo-33943: Add references in the docs for logging.basicConfig (GH-7858) by miss-islington · Pull Request #7899 · python/cpython

…GH-7858)

Adds references to info about file modes, `time.strftime()`, string formatting
syntaxes, and logging levels.
(cherry picked from commit a8ddf85)

Co-authored-by: Andrés Delfino <adelfino@gmail.com>