7 files declare their use of GeneratorInterface in Style Guide 8

CommentStyleguide.php in src/Plugin/Styleguide/CommentStyleguide.php

DefaultStyleguide.php in src/Plugin/Styleguide/DefaultStyleguide.php

ImageStyleguide.php in src/Plugin/Styleguide/ImageStyleguide.php

LayoutStyleguide.php in src/Plugin/Styleguide/LayoutStyleguide.php

SearchStyleguide.php in src/Plugin/Styleguide/SearchStyleguide.php

StyleguideForm.php in src/Form/StyleguideForm.php

StyleguideMaintenancePageController.php in src/Controller/StyleguideMaintenancePageController.php