* Use f-strings instead of .format()
* Code block language marker fixes
* Make example code blocks syntactically valid Python
* Run all python code blocks through black
https://github.com/scop/misc/blob/master/black_markdown.py
* Add some missing code block language markers
* Use shell language consistently to mark shell code blocks
* Undo folding of some example dicts
* Remove outdated OrderedDict comments per Python 3.7, replace with plain dict
The import and decorator syntax was Python 3.4, with Python 3.5 this
became much nicer and the async keyword is now used.
Use awaited instead of yielded, which makes it easier to read.
