doc: extensions: kconfig: fix module prefix handling
doc: extensions: kconfig: fix module prefix handling

If two modules started with the same prefix, e.g. nrf and nrfxlib, the
file name prefix was incorrectly set with the common prefix. Include
trailing "/" to the comparison, so that we match the full module name.

Signed-off-by: Gerard Marull-Paretas <bedb45f43a286e49f4dcda039a436b216ae61ef3@nordicsemi.no>

zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr