No longer uses incorrect message index when changing messages.
known (~(put by known) uid.gam count)
==
:: changed message
- =+ dex=(sub count u.old)
%_ +>.$
grams %+ welp
- (scag (dec dex) grams)
- [gam (slag dex grams)]
+ (scag (dec u.old) grams)
+ [gam (slag u.old grams)]
==
::
++ sa-change-remote ::< apply remote's delta
