feat: add more context to send_msg errors

deltachat-jsonrpc/src/api.rs

@@ -1946,9 +1946,13 @@ impl CommandApi {
 
     async fn send_msg(&self, account_id: u32, chat_id: u32, data: MessageData) -> Result<u32> {
         let ctx = self.get_context(account_id).await?;
-        let mut message = data.create_message(&ctx).await?;
+        let mut message = data
+            .create_message(&ctx)
+            .await
+            .context("Failed to create message")?;
         let msg_id = chat::send_msg(&ctx, ChatId::new(chat_id), &mut message)
-            .await?
+            .await
+            .context("Failed to send created message")?
             .to_u32();
         Ok(msg_id)
     }