Chore: Format code using Ruff

[amotl]

What the title says.

[codecov]

Codecov Report

Attention: Patch coverage is 77.27273% with 10 lines in your changes missing coverage. Please review.

Project coverage is 86.23%. Comparing base (403a922) to head (af74fc9).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
grafana_wtf/core.py	77.27%	5 Missing ⚠️
grafana_wtf/util.py	75.00%	2 Missing ⚠️
grafana_wtf/model.py	0.00%	1 Missing ⚠️
grafana_wtf/report/tabular.py	75.00%	1 Missing ⚠️
grafana_wtf/report/textual.py	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #170      +/-   ##
==========================================
+ Coverage   86.20%   86.23%   +0.02%     
==========================================
  Files           9        9              
  Lines        1109     1104       -5     
==========================================
- Hits          956      952       -4     
+ Misses        153      152       -1     

Flag	Coverage Δ
unittests	86.23% <77.27%> (+0.02%)	⬆️

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