hacking: Document header inclusion guard preferences

3 jobs for pragma-once in 3 minutes and 15 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #4152
librem5
build-debian-clang

00:02:23

passed #4151
librem5
build-debian-gcc

00:02:13

24.8%
passed #4153
librem5
build-debian-package

00:02:03