add function to reset the UART back to USB

libs/core/shims.d.ts

@@ -760,6 +760,15 @@ declare namespace serial {
     //% blockId=serial_redirect block="serial|redirect to|TX %tx|RX %rx|at baud rate %rate"
     //% blockExternalInputs=1 shim=serial::redirect
     function redirect(tx: SerialPin, rx: SerialPin, rate: BaudRate): void;
+
+    /**
+     * Reset the serial instance to use the USBTX and USBRX at the default baud rate.
+     */
+    //% weight=10
+    //% help=serial/reset
+    //% blockId=serial_reset block="serial pin reset"
+    //% blockExternalInputs=1 shim=serial::reset
+    function reset(): void;
 }