include option to ignore the suffix <suffix> is not defined warning.

[Mirko Hernández]

I did not found a way to ignore the "suffix is not defined" warnings.
Must all the commands used in a given prefix always be previously defined?. This makes the prefix unusable until all the commands are valid.

[Jonas Bernoulli]

As the error message mentions, it is enough if the command is autoloaded.

If you want to add a command from a package that may not be installed, then you can either add the suffix command to the prefix in the package that defines the command, using transient-insert-suffix, or you can use the :if property like so:

(transient-define-prefix example ()
  [("a" "undefined" undefined-command
    :if (lambda () (commandp 'undefined-command)))
   ("b" "next-line" next-line)])