message: stabilize take_storage
diff: @@ -319,8 +319,6 @@ mod sys {
  output_ptr: Ptr32Mut<[u8]>,
  ) -> ReturnCode;
  - /// **WARNING**: this function is from the [unstable interface](https://github.com/paritytech/substrate/tree/master/frame/contracts#unstable-interfaces),
  - /// which is unsafe and normally is not available on production chains.
  pub fn take_storage(
  key_ptr: Ptr32<[u8]>,
  key_len: u32,
  