[MrBeldum]

BlackWordsFn is documented as using a func to get the word list, but it called fn() once when the middleware was constructed and then behaved exactly like BlackWords with a frozen list. Any runtime change to the list (e.g. reloaded config) was silently ignored.

This change moves the body-inspection logic into a shared internal blackWords(func() []string) helper:

• BlackWords(words...) wraps the static slice in a closure (behaviour unchanged).
• BlackWordsFn(fn) now calls fn on every request, so updates are picked up.

Added TestBlackwordsFnDynamic, which changes the list after the middleware is created and checks that the next requests use the new list. It fails on the current code and passes with this change. go test -race ./... and go vet pass.