boards/seeedstudio-sensecap-t1000e: update doc.md

Co-authored-by: crasbe <crasbe@gmail.com>

Author: baptleduc

boards/seeedstudio-sensecap-t1000e/doc.md

@@ -104,7 +104,9 @@ By default, `stdio` uses `UART_DEV(1)` (P0.16/P0.17).
 `UART_DEV(0)` is reserved for the GNSS module. Connect a USB-to-UART adapter
 to P0.16 (TX) and P0.17 (RX) to access the terminal.
 
-To use USB CDC ACM (virtual serial port over the existing USB cable) instead:
+To use USB CDC ACM (virtual serial port over the existing USB cable) instead,
+you can add `USEMODULE+=stdio_cdc_acm` to your application's Makefile or to
+the compiler call:
 ```shell
 USEMODULE=stdio_cdc_acm BOARD=seeedstudio-sensecap-t1000e make -C examples/basic/hello-world flash term
 ```