rename event and mention event in method documentation

deltachat-jsonrpc/src/api.rs

@@ -232,6 +232,10 @@ impl CommandApi {
     }
 
     /// Performs a background fetch for all accounts in parallel with a timeout.
+    /// 
+    /// The `BackgroundFetchCompletedForAllAccounts` event is emitted at the end,
+    /// process all events until you get this one and you can safely return to the background
+    /// without forgeting to create notifications caused by timing race conditions.
     async fn background_fetch_for_all_accounts(&self, timeout_in_seconds: f64) -> Result<()> {
         self.accounts
             .write()