index: replace insert(-1, e) method by append(e) method I want to make index[len(index) - 1] be the tip revision, not null revision as it is today. insert(-1, e) will then make little sense. Since insert() currently requires the first argument to be -1, it seems simpler to replace it by a method that allows insertion only at the end. Note that revlogoldindex already has this method (by virtue of extending list). Differential Revision: https://phab.mercurial-scm.org/D4021