Add function to get source of error

src/util/error.rs

@@ -111,6 +111,12 @@ impl Error {
         }
     }
 
+    /// Get the original cause of this error
+    /// Like `std::error::Error::source` but doesn't return an `Option`
+    pub fn source(&self) -> &ErrorType {
+        &self.source
+    }
+
     /// Display this error as a modal dialog activated by a checkbox with the given id
     pub fn as_modal(&self, id: String) -> Element {
         rsx! {