revset.bisect: add 'ignored' set to the bisect keyword The 'ignored' changesets are outside the bisection range, but are changesets that may have an impact on the outcome of the bisection. For example, in case there's a merge between the good and bad csets, but the branch-point is out of the bisection range, and the issue originates from this branch, the branch will not be visited by bisect and bisect will find that the culprit cset is the merge. So, the 'ignored' set is equivalent to: ( ( ::bisect(bad) - ::bisect(good) ) | ( ::bisect(good) - ::bisect(bad) ) ) - bisect(range) - all ancestors of bad csets that are not ancestors of good csets, or - all ancestors of good csets that are not ancestors of bad csets - but that are not in the bisection range. Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>