docs/library: Clarify that the arg to esp.deepsleep is in microseconds.
@@ -31,7 +31,7 @@ Functions
The system enters the set sleep mode automatically when possible.
-.. function:: deepsleep(time=0, /)
+.. function:: deepsleep(time_us=0, /)
**Note**: ESP8266 only - use `machine.deepsleep()` on ESP32
