revlog: reorder index accessors to match data structure order Index entries are ordered tuples. We have accessors in the revlog class to map tuple offsets to names. To help reinforce the order, reorder the methods so they match the order of elements in the tuple. While I'm here, also sneak in some minimal documentation.

color: add the ability to display configured style to 'debugcolor' The 'hg debugcolor' command gains a '--style' flag to display all the configured labels and their styles. This have many benefits: * discovering documented label, * checking consistency between label's style, * showing the actual style of a label.