use serde deserializer functions to remove duplicated structs, remove TryFrom impls, replace Language enum with wrapper around isolang Language type

src/error.rs

@@ -171,6 +171,11 @@ pub enum IdQueryResultError {
     IdQueryResult(#[from] IdQueryResponseError),
 }
 
+#[derive(Debug, Error)]
+pub enum PublicationDemographicError {
+    InvalidValue,
+}
+
 #[derive(Debug, Error, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct ApiError {
@@ -208,6 +213,14 @@ impl fmt::Display for ChapterImagesContentError {
     }
 }
 
+impl fmt::Display for PublicationDemographicError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::InvalidValue => "InvalidValue".fmt(f),
+        }
+    }
+}
+
 impl serde::de::Error for JsonError {
     fn custom<T: fmt::Display>(msg: T) -> Self {
         JsonError::Message(msg.to_string())