Updates: message for preserved settings error.

src/commands/edge_app_manifest.rs

@@ -761,7 +761,7 @@ settings:
         let result = EdgeAppManifest::ensure_manifest_is_valid(&file_path);
         assert!(result.is_err());
         assert!(result.unwrap_err().to_string().contains( 
-            "Setting \"screenly_setting\" cannot start with \"screenly_\""
+            "Setting \"screenly_setting\" cannot start with \"screenly_\" as this prefix is preserved."
         ));
     }
 

src/commands/edge_app_settings.rs

@@ -90,7 +90,7 @@ where
         }
         if setting.name.starts_with("screenly_") {
             return Err(serde::de::Error::custom(format!(
-                "Setting \"{}\" cannot start with \"screenly_\"",
+                "Setting \"{}\" cannot start with \"screenly_\" as this prefix is preserved.",
                 setting.name
             )));
         }