Awesome

help-vsplit.nvim

Open vim help into a vertical split from the right or left of the current window if there is enough space for it. If space is not enough the help be opened in the horizontal split as it by default in Vim.

To install and activate with packer:

use { 'anuvyklack/help-vsplit.nvim'
   config = function()
      require('help-vsplit').setup()
   end
}

Configuration

In the setup() function you can pass the table with desired settings. Defaults are the next:

{
   always = false, -- Always open help in a vertical split.
   side = 'right', -- 'left' or 'right'
   buftype = { 'help' },
   filetype = { 'man' }
}

Open help in a vertical split on the far right

For this you don't need plugin. Add into file

$HOME/.config/nvim/after/ftplugin/help.vim

the next line

wincmd L