The "Programmers" content is specified in the file "programmers.txt" in the board package. Try to empty that file if you want to; the list of programmers should be empty after that. The currently selected entry might still be shown; in that case I think that deleting the directory C:\Users\yourUsernam\AppData\Roaming\arduino-ide (assuming Windows) should solve that problem.
Thank you, I tried delete that directory follow your answer and my problem has been solved.
But I wonder about other users that use my package, when I update package this problem will occur to those Users? Those Users have to delete that dirictory?
Not answering the question but I'm curious why the list of programmers and the selected programmer bothers you or why you think that it would bother users of your board package?
Very cool that you are creating a new Arduino package!
Have you published it online yet? If so, please post a link here. I try to be aware of the ecosystem of Arduino packages, both for my work at Arduino, as well as for my personal project of maintaining a list of all of them.
I think the only reason you saw entries in the Tools > Programmer menu is because you had started Arduino IDE at a time when your programmers.txt file did contain entries. Unfortunately for some reason Arduino IDE caches the contents of the Tools > Programmer menu, so once you did that the cache was populated with the entries from the programmers.txt file, and due to a bug, the cache was not updated even after you removed the entries from the file.
If so, the users won't encounter this problem because the programmers.txt file will be empty when they install the platform and so the cache will never be populated with menu entries for your board.