histedit: display action being processed in debug mode This is very useful when debugging histedit.

histedit: fold in memory Update the folding code to works in memory instead of applying patches on the working directory. This is cleaner, faster and prepare the removal of the whole patching logic. This new collapse function will probably move into core sooner or later. A lot of other rewriting operation may benefit from it.

histedit: move makedesc function near other rules related function Having it in the middle of action logic is confusing