random.nim: add a warning about crypo; refs #5047
random.nim: add a warning about crypo; refs #5047

tulayang/Nim,russpowers/Nim,russpowers/Nim,russpowers/Nim,dom96/Nim,dom96/Nim,tulayang/Nim,tulayang/Nim,dom96/Nim,dom96/Nim,tulayang/Nim,dom96/Nim,russpowers/Nim,tulayang/Nim,dom96/Nim,russpowers/Nim,tulayang/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim