message: Stabilize `seal_debug_message`
  Follow-up to
diff: @@ -331,6 +331,9 @@ mod sys {
  input_len: u32,
  output_ptr: Ptr32Mut<[u8]>,
  );
  +
  + #[cfg(feature = "ink-debug")]
  + pub fn seal_debug_message(str_ptr: Ptr32<[u8]>, str_len: u32) -> ReturnCode;
  }
  #[link(wasm_import_module = "seal1")]
  @@ -345,9 +348,6 @@ mod sys {
  #[link(wasm_import_module = "__unstable__")]
  extern "C" {
  - #[cfg(feature = "ink-debug")]
  - pub fn seal_debug_message(str_ptr: Ptr32<[u8]>, str_len: u32) -> ReturnCode;
  -
  pub fn seal_rent_params(
  output_ptr: Ptr32Mut<[u8]>,
  output_len_ptr: Ptr32Mut<u32>,
  