Display a warning message made from (format MESSAGE ARGS...).
Aside from generating the message with `format',
this is equivalent to `display-warning'.
TYPE is the warning type: either a custom group name (a symbol),
or a list of symbols whose first element is a custom group name.
(The rest of the symbols represent subcategories and
can be whatever you like.)
LEVEL should be either :debug, :warning, :error, or :emergency
(but see `warning-minimum-level' and `warning-minimum-log-level').
:emergency -- a problem that will seriously impair Emacs operation soon
if you do not attend to it promptly.
:error -- invalid data or circumstances.
:warning -- suspicious data or circumstances.
:debug -- info for debugging only. (fn TYPE LEVEL MESSAGE &rest ARGS)