docs: Document that validate and filter remove excess columns

[ytausch]

Motivation

Despite being a tested behaviour, documentation currently lacks the fact that Schema.validate() and Schema.filter() methods remove columns not being present in the schema.

Changes

Docstrings adjusted accordingly.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (4164a53) to head (f575744).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #264   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           53        53           
  Lines         3110      3110           
=========================================
  Hits          3110      3110           

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[borchero]

Thanks!