"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