Add table-of-contents in the "Commands and options" section

[lorenzo-cavazzi]

As a follow-up to #3033 , and as suggested here https://github.com/SwissDataScienceCenter/renku-python/pull/3065#issuecomment-1214743564 , we might want to expand the new "Commands and options" sections in the commands documentation by adding a "table of content" section. That should list the subcommands, and clicking should scroll down to the one selected. Since that section is automatically created, it would be nice to automatize the table-of-contents creation as well -- in a similar fashion to what we do with the cheat sheet. Doing it manually seems more error-prone.

We will have something like the following. Please ignore the styling; that should be more in line with what we see when scrolling to the bottom here.

P.S. We already explored a different solution adding the sub-commands to the nav bar, but that turned out to be too verbose https://github.com/SwissDataScienceCenter/renku-python/pull/3065#issuecomment-1211759312