message: Add doc comment for `ChunkWithProof` struct
diff: @@ -7,6 +7,8 @@ use casper_types::{
  use crate::{error, Digest};
  +/// Represents the chunk of data with attached [IndexedMerkleProof].
  +/// Empty data is always represented as single, empty chunk and not as zero chunks.
  #[derive(PartialEq, Debug, schemars::JsonSchema, serde::Serialize, serde::Deserialize)]
  #[schemars(with = "String", description = "Hex-encoded hash digest.")]
  #[serde(deny_unknown_fields)]
  