Thank you for your efforts,

Whenever I quit opened help files, this mesage is invoked

It said that it needs to set filetype, but the help file is already set to 'help'
What I am missing?

this is my config

{
	-- rendering help using vimdoc treesitter
	"OXY2DEV/helpview.nvim",
	lazy = false, -- Recommended
	enabled = true,
	dependencies = {
		"nvim-treesitter/nvim-treesitter"
	}
}