reitit: reload routes and handler changes

[practicalli-johnny]

Document a nice way to add reitit.ring/reloading-ring-handler to a web service so that reitit ring will re-creates router for every request, should take less than 1 millisecond.

References

https://clojurians.slack.com/archives/C7YF1SBT3/p1720545266287869