examples: use PW_KEY_TARGET_OBJECT

In examples, tell people how to use target.object.

src/examples/video-src-fixate.c

@@ -578,7 +578,7 @@ int main(int argc, char *argv[])
 	 * the server.  */
 	pw_stream_connect(data.stream,
 			  PW_DIRECTION_OUTPUT,
-			  PW_ID_ANY,			/* link to any node */
+			  PW_ID_ANY,
 			  PW_STREAM_FLAG_DRIVER |
 			  PW_STREAM_FLAG_ALLOC_BUFFERS,
 			  params, 2);