stack: use stack._revs instead of stack.revs[1:] in external children revset The revset in question excludes all revs that are part of the stack. Using stack.revs[1:] works (rev #0 is stack base, which is not a part of the stack), but using stack._revs is technically more correct, because this variable is specifically designed to hold only revisions that are part of the stack.

test: update output to match the parent changesets This amend was forgotten.