message: Add comment on re-compilation
diff: @@ -135,6 +135,10 @@ where
  }
  // Re-compile module from wasm
  + //
  + // This is needed for chains that upgrade their node software in a way that changes the module
  + // serialization format. If you do not replay all transactions, previous calls of `save_wasm`
  + // stored the old module format.
  let wasm = self.load_wasm(checksum)?;
  self.stats.misses += 1;
  let module = compile_and_use(&wasm, options.memory_limit)?;
  