fix: only use vim.iter if available to avoid accidental breaking ch…

…ange

lua/ibl/utils.lua

@@ -425,7 +425,8 @@ end
 ---@vararg T
 ---@return T
 M.tbl_join = function(...)
-    return vim.iter({ ... }):flatten():totable()
+    ---@diagnostic disable-next-line: deprecated
+    return vim.iter and vim.iter({ ... }):flatten():totable() or vim.tbl_flatten { ... }
 end
 
 ---@generic T