* docs/conf/overview: Add hint about cookie prefixes to --cookie-name
Cookie Prefixes further restricts the possibilities of session attacks because supporting clients will only accept cookies with one of the prefix if certain requirements were meet, see https://developer.mozilla.org/en-US/docs/Web/HTTP/Cookies#cookie_prefixes
* Backport cookie prefixes to older docs
Co-authored-by: Joel Speed <Joel.speed@hotmail.co.uk>