docs: Improve 01_concepts

[strakam]

• fix logical error for done
• add references to issues
• make some parts of the document more visually pleasing

idk how to add label :(

• I have added the correct label(s) to this Pull Request or linked the relevant issue(s)
• I have provided a description of the changes in this Pull Request
• I have added documentation for my changes and have listed relevant changes in CHANGELOG.md
• If applicable, I have added tests to cover my changes.
• I have reformatted the code using poe format
• I have checked style and types with poe lint and poe type-check
• (Optional) I ran tests locally with poe test
  (or a subset of them with poe test-reduced) ,and they pass
• (Optional) I have tested that documentation builds correctly with poe doc-build

[codecov-commenter]

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.28%. Comparing base (16f2fc2) to head (35c4cee).
Report is 4 commits behind head on master.

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1221      +/-   ##
==========================================
- Coverage   85.29%   85.28%   -0.02%     
==========================================
  Files         102      102              
  Lines        9078     9078              
==========================================
- Hits         7743     7742       -1     
- Misses       1335     1336       +1     

Flag	Coverage Δ
unittests	85.28% <ø> (-0.02%)	⬇️

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