* Add action to check board headers when modified
* Fix invalid escape warning
* Check for more board header errors before exiting script
* Also run when action file changes
* Add back newline at end of check_all_board_headers.sh
* Remove python install step
* `e.__str__()` -> `str(e)`
* Add script to automatically validate board header files
* Fix small automatically-found inconsistencies in various board header files
* Tweak and add board header file from abandoned PR #1174