Trying to get comment toggling to work with unsupported language

Hi, i am new to Neovim. I am using the lunarvim distro. I like the comment toggling feature, but sadly treesitter does not directly support my language (vhdl). So I tried doing this in my config.lua:

lvim.builtin.treesitter.context_commentstring.config.vhdl = "-- %s"

and it works. But only after I type stuff like :h or :TSUpdate or reopened the config.lua file, I haven’t quite figured out the pattern. Obviously I don’t want to do this on any new neovim session. Can someone help me set it up properly?