dirstate-guard: remove usage in `rebase` Now that the dirstate change and write are clearer, it does not seems we need to use a dirstate-guard here anymore. The transaction already wrap the full operation.

dirstate-guard: remove it usage in `mq` The code it covered is also covered by a `changing_parents` context.

dirstate: enforce the use of `changing_files` context to change tracking Now that everything is using the new context, we can start enforcing its usage.