docs(gen): support language annotation in docstrings

src/nvim/api/buffer.c

@@ -84,7 +84,7 @@ Integer nvim_buf_line_count(Buffer buffer, Error *err)
 ///
 /// Example (Lua): capture buffer updates in a global `events` variable
 /// (use "print(vim.inspect(events))" to see its contents):
-/// <pre>
+/// <pre>lua
 ///   events = {}
 ///   vim.api.nvim_buf_attach(0, false, {
 ///     on_lines=function(...) table.insert(events, {...}) end})