message: Add missing tag to inlined endorsement
diff: @@ -260,6 +260,7 @@ Endorsement (tag 21)
  #[derive(Debug, Clone, serde::Serialize, serde::Deserialize, HasEncoding, NomReader, BinWriter)]
  #[serde(tag = "kind", rename_all = "snake_case")]
  pub enum InlinedEndorsementMempoolContents {
  + #[encoding(tag = 21)]
  Endorsement(InlinedEndorsementMempoolContentsEndorsementVariant),
  }
  