wrap the keymap settings in autocmd

lua/lazyvim/plugins/extras/lang/tex.lua

@@ -30,9 +30,15 @@ return {
       vim.g.vimtex_quickfix_method = vim.fn.executable("pplatex") == 1 and "pplatex" or "latexlog"
 
       vim.g.vimtex_mappings_enabled = false
+
+      local augroup = vim.api.nvim_create_augroup("vimtexConfig", {})
+      vim.api.nvim_create_autocmd("FileType", {
+        pattern = "tex",
+        group = augroup,
+        callback = function(event)
           local wk = require("which-key")
           wk.add({
-        -- buffer = ev.buf, -- e.g. ev.buf or similar
+            buffer = event.buf,
             {
               "<localleader>l",
               group = "VimTeX",
@@ -536,6 +542,8 @@ return {
             },
           })
         end,
+      })
+    end,
     keys = {
       { "<localLeader>l", "", desc = "+vimtex", ft = "tex" },
     },