Re: [PATCH] reset: update help text

> [1] Detailed semantics: for each path listed by "git diff --name-only
> HEAD <commit>":
>
>  * if the worktree, index, and HEAD match, make the index and worktree
>    match <commit>.
>
>  * otherwise, if it is "not easy" to keep local changes, error out.
>    We are not going to do a three-way merge.  That is,
>
>    - if the index matches neither HEAD nor <commit>, error out;
>    - if the index matches HEAD but not the worktree, error out.
>
>  * otherwise, it is "easy", so keep local changes.
>
>    - if the index already matches <commit>, leave the index and
>      worktree alone.
>    - if the index and worktree match HEAD, make them match the
>      <commit> instead.