add hpack

lua/config/hpack.lua

@@ -1,6 +1,5 @@
 local function hpack()
-    local file = vim.fn.expand("%")
-    local err = vim.fn.system("hpack " .. file)
+    local err = vim.fn.system("hpack")
     if vim.v.shell_error ~= 0 then
         print(err)
     end
@@ -10,3 +9,8 @@ vim.api.nvim_create_autocmd("BufWritePost", {
     pattern = "package.yaml",
     callback = hpack,
 })
+
+vim.api.nvim_create_autocmd("BufEnter", {
+    pattern = "*.hs",
+    callback = hpack,
+})