completion : session_tokens insert range in completion tool (no-op → correct) (ggml-org#20917)

The embd.begin(), embd.begin() range is empty and inserts nothing, so session_tokens never gets updated after
  decoding. Should be embd.begin(), embd.end(). Introduced in commit ef66a16.

Author: mtmcp

tools/completion/completion.cpp

@@ -701,7 +701,7 @@ int main(int argc, char ** argv) {
                 if (!common_prompt_batch_decode(ctx, embd, n_past, params.n_batch, path_session, save_now)) {
                     return 1;
                 }
-                session_tokens.insert(session_tokens.end(), embd.begin(), embd.begin());
+                session_tokens.insert(session_tokens.end(), embd.begin(), embd.end());
                 n_session_consumed = session_tokens.size();
                 session_do_save = false;