chgbar – Draw change bars in the margin

De­fines macros \chg­bar­be­gin and \chg­barend to mark the ex­tent of changes to the doc­u­ment. The change bar is drawn con­tin­u­ously be­tween the lines con­tain­ing the two macros, but there are is­sues due to the tim­ing of glue set in the ver­ti­cal stretch­a­bil­ity of the page.