#3354 fix(templates): Fix class docstrings in tap, target and mapper templates Pull request opened by edgarrmondragon ## Summary by Sourcery Update class docstrings in cookiecutter mapper, tap, and target templates for improved consistency and clarity. Documentation: • Standardize mapper class docstrings to 'Mapper for '. • Clarify tap class docstrings to 'Singer tap for ' in both non-SQL and SQL templates. • Refine target class docstrings to 'Target for '. meltano/sdk