Make the withheld reason part of the error message

Author: poljar

crates/matrix-sdk-crypto/src/error.rs

@@ -88,7 +88,7 @@ pub enum MegolmError {
 
     /// Decryption failed because we're missing the room key that was to encrypt
     /// the event.
-    #[error("Can't find the room key to decrypt the event")]
+    #[error("Can't find the room key to decrypt the event, withheld code: {0:?}")]
     MissingRoomKey(Option<WithheldCode>),
 
     /// Decryption failed because of a mismatch between the identity keys of the

crates/matrix-sdk-crypto/src/machine.rs

@@ -1360,7 +1360,6 @@ impl OlmMachine {
                 _ => {}
             }
 
-            // TODO: log the withheld reason if we have one.
             warn!("Failed to decrypt a room event: {e}");
         }