Try to be more smart while parsing `--config-patch` (and similar) flags:
* we still support inline patches
* if the flag value doesn't look like a patch, try to use it as a
filename directly
This avoids common confusion with `--config-patch=patch.yaml` returning
an error "expected a mapping node".
Also clarify/updated documentation for `talosctl edit` and `talosctl
patch`, as they only work for the machineconfig, there is no other
usecase now.
Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>
(cherry picked from commit e2ee39b8ac54ada49dd0a7ffaab4b0ae5d684792)
9a2f6d9c9e