descriptor: impl error for DescriptorKeyParseError

Signed-off-by: Antoine Poinsot <[email protected]>

Author: darosior

src/descriptor/mod.rs

@@ -104,6 +104,16 @@ impl fmt::Display for DescriptorKeyParseError {
     }
 }
 
+impl std::error::Error for DescriptorKeyParseError {
+    fn description(&self) -> &str {
+        ""
+    }
+
+    fn cause(&self) -> Option<&std::error::Error> {
+        None
+    }
+}
+
 impl fmt::Display for DescriptorPublicKey {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {