Enable mapping function with which-key-helper.register_with_editable()

[Toraja]

Summary

• To map function, caller must pass function as command (e.g. lua f())
• Modify wrap_as_cmd() so that it wraps only if the given command is not function
  • Trade off is that it is not possible to edit the command.
  • So wrap_as_editable() should not be run for function reference.

[Toraja]

Closing as the downside that is being uneditable is greater