man: fix no-auto-default state dir in NetworkManager.conf manual

Quote from `man NetworkManager.conf`:

  When the default wired connection is deleted or saved to a new
  persistent connection by a plugin, the device is added to a list in the
  file /run/NetworkManager/no-auto-default.state to prevent creating
  the default connection for that device again.

/run is obviously wrong. Fix it.
4 jobs for th/fix-doc-no-auto-default-file in 14 minutes and 11 seconds (queued for 9 minutes and 41 seconds)
Status Job ID Name Coverage
  Test
passed #34189
allowed to fail
checkpatch

00:01:10

passed #34190
f28_build_default

00:13:01

passed #34191
f28_rpm_autotools_dbg

00:13:00

passed #34192
f28_rpm_meson_dbg

00:11:52