Arbitrary instance for Symbol

[phipsgabler]

Is there a specific reason that there is no default Arbitrary instance for Symbol? If not, could you just add something along the lines of

implicit lazy val arbSymbol: Arbitrary[Symbol] =
  Arbitrary(arbitrary[String].map(Symbol(_)))

?

[non]

Unfortunately the obvious way to add this implicit breaks binary compatibility (according to MiMA). We could probably work around this by adding a new trait for object Arbitrary to extend, but I'll wait until I hear from @rickynils about if (or when) he wants to add this implicit and how.