Boards documentation: "arm" Architecture not specified at least for STM32MP13 and STM32N6 boards

[arnopo]

Describe the bug

For the following ST boards, no arm architecture is specified in the documentation. When using the architecture filter to select ARM SoCs, these boards are not listed:

Nucleo N657X0-Q
STM32N6570-DK
STM32MP135F-DK
For example, the following link shows the STM32MP13 board:
https://docs.zephyrproject.org/4.2.0/boards/index.html#vendor=st&soc=stm32mp135fxx

However, the board does not appear when adding the arm architecture filter:
https://docs.zephyrproject.org/4.2.0/boards/index.html#vendor=st&soc=stm32mp135fxx&arch=arm

A preliminary analysis shows that for these boards, the arch: arm attribute is defined in twister.yaml instead of the respective .yaml file.

Seems that twister.yaml should be parsed by default or the twister.yml files should be renamed.

other boards potentially impacted:

./boards/others/stm32_min_dev/
./boards/intel/adsp/
./boards/mediatek/

Impact

Annoyance – Minor irritation; no significant impact on usability or functionality.

[JarmouniA]

Seems that twister.yaml should be parsed by default or the twister.yml files should be renamed

Unrelated to the reported bug, I think it will be good to enforce naming this file twister.yaml, so that its purpose becomes clear for everyone.