Merge branch 'jc/ll-merge-internal'

"git rerere" can get confused by conflict markers deliberately left by the inner merge step, because they are indistinguishable from the real conflict markers left by the outermost merge which are what the end user and "rerere" need to look at. This was fixed by making the conflict markers left by the inner merges a bit longer. * jc/ll-merge-internal: t6036: remove pointless test that expects failure ll-merge: use a longer conflict marker for internal merge ll-merge: fix typo in comment