It looks like the difference is in the ST-provided SVDs. The L4 reference manual calls it EXTI15_10, the WB reference manual calls it EXTI[15:10]. It looks like the C headers use EXTI15_10 in both, and all the other STM32s call it EXTI15_10 too; the WB55 is the only one in stm32-rs that uses EXTI10_15.

At least it's pretty clear which way it should go! The fix will be adding an entry to devices/stm32wb55.yaml to rename the interrupt. Something like (untested):

EXTI:
    _modify:
        _interrupts:
            EXTI10_15:
                name: EXTI15_10