CRSFProtection plugin: improve documentation
CRSFProtection plugin: improve documentation

Give a hint/note to devs to detach from the execution chain when using a
custom controller method to detach to after CSRF check failed.

cutelyst/cutelyst,buschmann23/cutelyst,buschmann23/cutelyst,cutelyst/cutelyst,cutelyst/cutelyst,buschmann23/cutelyst