Descripe the doc issue

There appears to be extra slashes (\) in usac.markdown as we can see in the documentation (search for \ \).

Fix suggestion

It seems like those slashes should be removed.

Also, older versions of that tutorial seem to be broken; i.e., I cannot change the version in the dropdown at the top of the page, e.g., to 4.6.0

Finally, should this tutorial be listed in the Table of Contents?