📝 clarify sync alias target behavior

docs/api/configured-logger.md

@@ -32,6 +32,7 @@ Detailed rules explaining key parameters and behaviors
 - This is a type alias, not a separate wrapper implementation.
 - It preserves normal logger methods such as `info(...)`, `warn(...)`, `error(...)`, and the other `Logger` APIs.
 - Because it is `Logger[RuntimeSink]`, it also keeps ordinary logger composition and target behavior such as `with_target(...)`, `child(...)`, and per-call `log(..., target=...)` overrides.
+- In particular, `log(..., target=...)` can override the target for one call, while severity helpers such as `info(...)`, `warn(...)`, and `error(...)` continue using the stored logger target unless code derives another logger first with `with_target(...)` or `child(...)`.
 - It also exposes configured runtime helpers such as `flush()`, `drain()`, `pending_count()`, `dropped_count()`, and file-specific controls when the runtime sink supports them.
 - Builders such as `build_logger(...)` and `parse_and_build_logger(...)` return this alias as the main sync config-to-runtime result.
 - `ApplicationLogger` is another direct alias-oriented name for this same configured runtime surface, while `LibraryLogger[RuntimeSink]` is the narrowing facade variant that intentionally hides these runtime helpers until `to_logger()` is used.
@@ -59,7 +60,18 @@ ignore(logger.pending_count())
 
 In this example, the alias keeps ordinary logging calls while still exposing runtime diagnostics.
 
-And the inherited logger target rules stay unchanged: `log(..., target=...)` can override the target per call, while `with_target(...)` and `child(...)` derive new logger values with changed default targets.
+And the inherited logger target rules stay unchanged: `log(..., target=...)` can override the target per call, while `info(...)`, `warn(...)`, and `error(...)` continue using the stored target unless code derives another logger first with `with_target(...)` or `child(...)`.
+
+#### When Need A One-call Target Override On The Configured Runtime Logger
+
+When config-built sync code should keep the same logger value but emit one record under a different target:
+```moonbit
+logger.log(Level::Error, "boom", target="svc.audit")
+```
+
+In this example, the emitted record uses `svc.audit` only for that one call.
+
+And later `info(...)`, `warn(...)`, or `error(...)` calls still use the logger's stored target unless code derives another logger first with `with_target(...)` or `child(...)`.
 
 ### Error Case