Devtools

* switch to [`executing`](https://pypi.org/project/executing/) and [`asttokens`](https://pypi.org/project/asttokens/)
for finding and printing debug arguments, 82, thanks alexmojaki
* correct changelog links, 76, thanks Cielquan
* return `debug()` arguments, 87
* display more generators like `map` and `filter`, 88
* display `Counter` and similar dict-like objects properly, 88
* display `dataclasses` properly, 88
* uprev test dependencies, 81, 83, 90

compatibility with python 3.8.6

* improve `__pretty__` to work better with pydantic classes, 52
* improve the way statement ranges are calculated, 58
* drastically improve import time, 50
* pretty printing for non-standard dicts, 60
* better statement finding for multi-line statements, 61
* colors in windows, 57
* fix `debug(type(dict(...)))`, 62

* fix python tag in `setup.cfg`, 46

* support `MultiDict`, 34
* support `__pretty__` method, 36

* remove use of `warnings`, include in output, 30
* fix rendering errors 31
* better str and bytes wrapping 32
* add `len` everywhere possible, part of 16