fix(markdown): create default numbered Headline groups for colorschemes that dont support them. Fixes #1822

lua/lazyvim/plugins/extras/lang/markdown.lua

@@ -67,9 +67,13 @@ return {
     opts = function()
       local opts = {}
       for _, ft in ipairs({ "markdown", "norg", "rmd", "org" }) do
-        opts[ft] = { headline_highlights = {} }
+        opts[ft] = {
+          headline_highlights = {},
+        }
         for i = 1, 6 do
-          table.insert(opts[ft].headline_highlights, "Headline" .. i)
+          local hl = "Headline" .. i
+          vim.api.nvim_set_hl(0, hl, { link = "Headline", default = true })
+          table.insert(opts[ft].headline_highlights, hl)
         end
       end
       return opts