Update changelog.txt

changelog.txt

@@ -11,6 +11,9 @@ Known issues:
 -- Group roster changes will not be reflected during combat  
 --   Swapping a player between groups during combat will cause  
 --   unpredictable, negative results.  Be warned!  
+-- Built-in Blizzard APIs for incoming healing only partially working  
+--   If other healers are using LibHealComm enable it under:  
+--   'VuhDo Options > General > Threat / Incoming > Incoming Heal > Use LibHealComm'  
   
   
 Bugfixes: