Correct spelling of two more words

Thanks Undeference for pointing out abreviations.

code/botlib/be_ai_chat.c

@@ -557,7 +557,7 @@ void StringReplaceWords(char *string, char *synonym, char *replacement)
 	while(str)
 	{
 		//if the synonym isn't part of the replacement which is already in the string
-		//useful for abreviations
+		//useful for abbreviations
 		str2 = StringContainsWord(string, replacement, qfalse);
 		while(str2)
 		{