docs: add pymarkdownlnt to lint jobs

[qlrd]

What is this PR for?

pymarkdownlnt is a nice lib that lints markdown documents. It check for good formatting and standards managed by CommonMark. As proof of concept, the linter was applied only to the README.md.

Changes made to:

• Code
• Tests
• Docs
• CHANGELOG

Did you build the code and tested on device?

• Yes, build and tested on

What is the purpose of this pull request?

• Bug fix
• New feature
• Docs update
• Other

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.31%. Comparing base (86340f3) to head (a6732e5).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #815   +/-   ##
========================================
  Coverage    97.31%   97.31%           
========================================
  Files           83       83           
  Lines        10576    10576           
========================================
  Hits         10292    10292           
  Misses         284      284           

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[odudex]

I think it's a great tool that contributors can spin locally and submit their results to the project.
But making project infrastructure slim has become a security priority.
Tracking decencies tree I wonder, does it worth it? I tried it locally and saw the poetry.lock file grows significantly, so I think we don't need to mandate its use.

pymarkdownlnt 0.9.34 A GitHub Flavored Markdown compliant Markdown linter.
├── application-properties >=0.9.0
│   ├── pyjson5 >=1.6.9 
│   ├── pyyaml >=5.4.1 
│   ├── tomli >=2.0.1 
│   └── typing-extensions >=4.5.0 
├── columnar >=1.4.0
│   ├── toolz * 
│   └── wcwidth * 
└── typing-extensions >=4.5.0

[qlrd]

We can add only on CI then, or close

[odudex]

I would repurpose the PR to lint files, the single one it targets now, or more, without adding weight to the project with tools and enforcements. It would be very welcome.