Adopt ruff and address lint

[blink1073]

cf jupyter-server/jupyter_server#1114

[bollwyvl]

Just as I see you pushing, but apropos of nothing:

Typing :: Typed

is now a trove classifier. Maybe we start using around the house?

[codecov-commenter]

Codecov Report

Base: 80.90% // Head: 80.89% // Decreases project coverage by -0.01% ⚠️

Coverage data is based on head (bf39f55) compared to base (7138c26).
Patch coverage: 76.13% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #343      +/-   ##
==========================================
- Coverage   80.90%   80.89%   -0.02%     
==========================================
  Files          22       22              
  Lines        1697     1701       +4     
  Branches      323      323              
==========================================
+ Hits         1373     1376       +3     
- Misses        224      225       +1     
  Partials      100      100              

Impacted Files	Coverage Δ
jupyterlab_server/settings_utils.py	78.50% <41.66%> (ø)
jupyterlab_server/process.py	67.51% <44.44%> (ø)
jupyterlab_server/app.py	83.33% <50.00%> (ø)
jupyterlab_server/settings_handler.py	78.04% <50.00%> (ø)
jupyterlab_server/handlers.py	78.78% <75.00%> (-0.49%)	⬇️
jupyterlab_server/workspaces_handler.py	88.80% <75.00%> (ø)
jupyterlab_server/workspaces_app.py	88.05% <80.00%> (ø)
jupyterlab_server/test_utils.py	67.07% <87.50%> (-0.40%)	⬇️
jupyterlab_server/_version.py	77.77% <100.00%> (+2.77%)	⬆️
jupyterlab_server/config.py	73.96% <100.00%> (ø)
... and 9 more

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[blink1073]

Maybe we start using around the house?

Done!