Change top_k type.

Is my lack of knowledge of the code base showing? Yes it is.

examples/server/server.cpp

@@ -162,7 +162,7 @@ struct llama_server_context
       const float temp = params.temp;
       // const int32_t top_k = params.top_k <= 0 ? llama_n_vocab(ctx) : params.top_k;
       const float top_p = params.top_p;
-      const float top_k = params.top_k;
+      const int32_t top_k = params.top_k <= 0 ? llama_n_vocab(ctx) : params.top_k;
       const float tfs_z = params.tfs_z;
       const float typical_p = params.typical_p;
       const int32_t repeat_last_n = params.repeat_last_n < 0 ? params.n_ctx : params.repeat_last_n;