Fix typo in comment

descriptors should be plural

Co-authored-by: Dan Halbert <[email protected]>

Author: FiriaCTO

tools/gen_usb_descriptor.py

@@ -739,7 +739,7 @@ def strings_in_order(cls):
   .url             = URL
 }};
 
-// These next two hardcoded descriptor were pulled from the usb_descriptor.c file
+// These next two hardcoded descriptors were pulled from the usb_descriptor.c file
 // of the tinyusb webusb_serial demo. TODO - this is probably something else to
 // integrate into the adafruit_usb_descriptors project...