meta: add note re: announcing default pill
meta: add note re: announcing default pill

Resolves #2735.

jfranklin9000/urbit,ngzax/urbit,jfranklin9000/urbit,ngzax/urbit,ngzax/urbit,urbit/urbit,jfranklin9000/urbit,urbit/urbit,ngzax/urbit,urbit/urbit,jfranklin9000/urbit,ngzax/urbit,ngzax/urbit,ngzax/urbit,jfranklin9000/urbit,urbit/urbit,jfranklin9000/urbit,urbit/urbit,urbit/urbit,urbit/urbit,jfranklin9000/urbit