muttcol fix

etc/muttcol

@@ -24,7 +24,7 @@ mono error bold
 color normal default default
 color indicator brightblack white
 color sidebar_highlight red default
-color sidebar_divider color8 black
+color sidebar_divider brightblack black
 color sidebar_flagged red black
 color sidebar_new green black
 color normal brightyellow default