HACKING: document using g_auto* is o.k.

Closes: #33
3 jobs for doc-g_auto in 7 minutes and 23 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build
passed build-debian-clang #3533
librem5

00:02:53

passed build-debian-gcc #3532
librem5

00:02:11

24.9%
passed build-debian-package #3534
librem5

00:02:18