* chore: update deprecated import from collections
* chore: remove outdated imports from markdown library
as it hasn't been supported since 2.0.3 and we're on 3.x.
This was deprecated at least as early as 2012!
* docs: add docstring and remove lint-amnesty to markdown plugin
* chore: remove deprecated etree import
* style: remove unnecessary-comprehension for sets
* style: resolve a number of amnestied pylint complaints
Co-authored-by: stvn <stvn@mit.edu>
d9dd10dc97