revset: mark spot that feeds a set to a baseset Sets have non-defined order and this should break stuff, but as we are lucky fullreposet is also broken so the result is "not too bad". We should fix it anyway, but it is too much for my current plate.

revset: mark the fact we should use '&' instead of 'filter' in 'head' I do not have time to fix all this now, let's mark it for later.