message: [lang] Rename some fields in the JSON api description
  They are now a bit more aligned to what substrate generates for modules etc.
diff: @@ -107,6 +107,7 @@ pub struct ParamDescription {
  /// The name of the parameter.
  name: String,
  /// The type of the parameter.
  + #[serde(rename = "type")]
  ty: TypeDescription,
  }
  @@ -131,14 +132,14 @@ impl TryFrom<&syn::ArgCaptured> for ParamDescription {
  #[derive(Debug, PartialEq, Eq, Deserialize, Serialize)]
  pub struct DeployDescription {
  /// The parameters of the deploy handler.
  - params: Vec<ParamDescription>,
  + args: Vec<ParamDescription>,
  }
  impl TryFrom<&hir::DeployHandler> for DeployDescription {
  type Error = Errors;
  fn try_from(deploy_handler: &hir::DeployHandler) -> Result<Self> {
  - let params = deploy_handler
  + let args = deploy_handler
  .decl
  .inputs
  .iter()
  @@ -152,14 +153,15 @@ impl TryFrom<&hir::DeployHandler> for DeployDescription {
  }
  })
  .collect::<Result<Vec<_>>>()?;
  - Ok(Self { params })
  + Ok(Self { args })
  }
  }
  /// Describes the return type of a contract message.
  #[derive(Debug, PartialEq, Eq, Deserialize, Serialize)]
  +#[serde(transparent)]
  pub struct ReturnTypeDescription {
  - #[serde(flatten)]
  + #[serde(rename = "type")]
  opt_type: Option<TypeDescription>
  }
  @@ -198,9 +200,9 @@ pub struct MessageDescription {
  /// If the message is allowed to mutate the contract state.
  mutates: bool,
  /// The parameters of the message.
  - params: Vec<ParamDescription>,
  + args: Vec<ParamDescription>,
  /// The return type of the message.
  - ret_ty: ReturnTypeDescription,
  + return_type: ReturnTypeDescription,
  }
  impl TryFrom<&hir::Message> for MessageDescription {
  @@ -211,7 +213,7 @@ impl TryFrom<&hir::Message> for MessageDescription {
  name: message.sig.ident.to_owned_string(),
  selector: message.selector().into(),
  mutates: message.is_mut(),
  - params: {
  + args: {
  message
  .sig
  .decl
  @@ -227,7 +229,7 @@ impl TryFrom<&hir::Message> for MessageDescription {
  })
  .collect::<Result<Vec<_>>>()?
  },
  - ret_ty: ReturnTypeDescription::try_from(&message.sig.decl.output)?,
  + return_type: ReturnTypeDescription::try_from(&message.sig.decl.output)?,
  })
  }
  }
  