doc: Small fixup on traceloop guide
@@ -49,7 +49,7 @@ result was saved in `/tmp/file-1889` but we attempted to open
We can close this trace now.
```
-$ kubectl gadget traceloop show 10.0.30.247_default_mypod
+$ kubectl gadget traceloop close 10.0.30.247_default_mypod
closed
```
