Fix a simple typo

Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>

Author: aspsk

advanced01-xdp-tc-interact/README.org

@@ -34,7 +34,7 @@ root qdisc lock (e.g. [[http://vger.kernel.org/lpc-bpf2018.html#session-1][Googl
 The XDP-project have a git-repo for demonstrating how to solve this:
 - https://github.com/xdp-project/xdp-cpumap-tc
 
-It setup the MQ (Multi-Queue) qdisc per TXQ to have a HTB-shaper. Then is
+It setup the MQ (Multi-Queue) qdisc per TXQ to have a HTB-shaper. Then it
 uses XDP to redirect (via CPUMAP) the traffic to the CPU that is responsible
 for handling this egress traffic. In the TC clsact-egress hook, a BPF-prog
 stamps the SKB packet with the appropriate HTB class id (via