dirstate-item: update the attribute documentation It was very outdated. We are about to change these attribute so we should has well have them documented so that the change get easier to grasp.

dirstate-item: use `any_tracked` more This simplify more code.

dirstate-item: drop an outdated comments This comment is no longer relevant since we moved away from the `state` internal representation, multiple weeks ago.

dirstate: remove a update_file's special case for `merged` file This case was fishy and can be dealt with by passing more accurate data a higher level. This clarify the API and prepare for a larger rework of the data we feeds to the dirstate.

dirstate: remove a update_file's special case for tracked file with p2 data This case was fishy and can be dealt with by passing more accurate data a higher level. This clarify the API and prepare for a larger rework of the data we feeds to the dirstate.

dirstate: deprecate `__getitem__` access If we want to drop `state` usage, we need to deprecate this. Differential Revision: https://phab.mercurial-scm.org/D11544

dirstate-item: use item's property instead of `state` in largefile Differential Revision: https://phab.mercurial-scm.org/D11543

dirstate-item: use `added` instead of `state` when moving dirstate Differential Revision: https://phab.mercurial-scm.org/D11542