AddUserFile
AddUserFile (filename)
Function AddUserFile is available to the _usermenu.lua script.
Parameter filename (its path is relative to the plugin’s directory)
specifies a file that is treated as an additional _usermenu.lua file.
All utilities added by AddToMenu and
AddCommand calls within the file specified by filename
share a common environment that does not change until the next
Reload User File operation (or until FAR termination).
In fact, the plugin itself executes AddUserFile("_usermenu.lua").