Issue #3414920 by quietone, m0d: Fix documentation redirects to Drupal 7 docs

core/USAGE.txt

core/assets/scaffold/files/default.settings.php

core/assets/scaffold/files/example.sites.php

core/core.api.php

core/lib/Drupal/Core/Database/database.api.php

core/modules/content_translation/content_translation.module

core/modules/contextual/contextual.module

core/modules/field_ui/field_ui.module

core/modules/menu_ui/menu_ui.module

core/modules/migrate/src/Plugin/migrate/source/SqlBase.php

core/modules/node/node.module

core/modules/shortcut/shortcut.module

...statistics/src/Plugin/migrate/destination/NodeCounter.php

core/modules/taxonomy/taxonomy.module

core/modules/toolbar/toolbar.module

sites/default/default.settings.php

sites/example.sites.php