docs: Directories and links aren't supported
Reported by QE.  Now separately we seemed not to fail trying to
do this for some reason; will investigate that.
Move the things we do support to the top for clarity.
@@ -26,15 +26,15 @@ Not all Ignition config sections are supported; see the following table:
Ignition sections | Supported
--- | ---
+Files | YES
+systemd Units | YES
Networkd | NO
Users | NO *
-Directories | YES
-Files | YES
+Directories | NO
FileSystems | NO
-Links | YES
+Links | NO
Disks | NO
RAID | NO
-systemd Units | YES
\* At this time only updates to `sshAuthorizedKeys` for user `core` are permitted. Please see [Update-SSHKeys](./Update-SSHKeys.md) for details.
