fix: properly handle other field in LanguageMsg

Change type of `other` field in the `LanguageMsg` type from `String` to
`Option<String>` because it is not always present.

src/model.in.rs

@@ -102,7 +102,7 @@ pub struct DidYouMean {
 pub struct LanguageMsg {
     // Attributes
     pub english: String,
-    pub other: String,
+    pub other: Option<String>,
 }
 
 /// Provides information for queries regarding a topic under development.

src/model.rs

@@ -37,6 +37,7 @@ mod tests {
         DidYouMeans,
         Img,
         Infos,
+        LanguageMsg,
         Plaintext,
         Pod,
         QueryResult,
@@ -68,6 +69,11 @@ mod tests {
         from_str::<QueryResult>(&read_sample_data_from_path("tests/sample-data/query_result_6.xml")).unwrap();
     }
 
+    #[test]
+    fn test_languagemsg_deserializer() {
+        from_str::<LanguageMsg>(&read_sample_data_from_path("tests/sample-data/languagemsg.xml")).unwrap();
+    }
+
     #[test]
     fn test_definitions_deserializer() {
         from_str::<Definitions>(&read_sample_data_from_path("tests/sample-data/definitions.xml")).unwrap();

tests/sample-data/languagemsg.xml

@@ -0,0 +1 @@
+<languagemsg english='Wolfram|Alpha does not yet support Slovak.' />