Update

nvim/after/ftplugin/tex.lua

@@ -0,0 +1,10 @@
+vim.api.nvim_create_autocmd({"FileType", "BufWinEnter"}, {
+  pattern = "*.tex",
+  callback = function(opts)
+    vim.keymap.set('n', "<leader>k", "<plug>(vimtex-doc-package)",
+      { desc = "[TeX] Show Package Documentation", buffer = opts.buf })
+  end
+
+})
+
+-- vim: ts=2 sts=2 sw=2 et