Add PHPStan sections in docs

[max-s-lab]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌
Fixed issues

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.48%. Comparing base (2fc017b) to head (097198f).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master   #20504   +/-   ##
=========================================
  Coverage     64.48%   64.48%           
  Complexity    11576    11576           
=========================================
  Files           433      433           
  Lines         37610    37610           
=========================================
  Hits          24252    24252           
  Misses        13358    13358           

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[samdark]

Thank you!