fix: fix backwards compatibility with neovim v0.9+

Author: mehalter

lua/astroui/init.lua

@@ -44,14 +44,16 @@ end
 ---@param fallback? table The fallback highlight properties
 ---@return table properties # the highlight group properties
 function M.get_hlgroup(name, fallback)
-  local hl = vim.api.nvim_get_hl(0, { name = name, link = false, create = false })
-  if not vim.tbl_isempty(hl) then
-    if not hl.fg then hl.fg = "NONE" end
-    if not hl.bg then hl.bg = "NONE" end
-    if hl.reverse then
-      hl.fg, hl.bg, hl.reverse = hl.bg, hl.fg, nil
+  if vim.fn.hlexists(name) == 1 then
+    local hl = vim.api.nvim_get_hl(0, { name = name, link = false })
+    if not vim.tbl_isempty(hl) then
+      if not hl.fg then hl.fg = "NONE" end
+      if not hl.bg then hl.bg = "NONE" end
+      if hl.reverse then
+        hl.fg, hl.bg, hl.reverse = hl.bg, hl.fg, nil
+      end
+      return hl
     end
-    return hl
   end
   return fallback or {}
 end