Update documentation on Chronology to include IslamicChronology in the list of included chronologies.
Update documentation on Chronology to include IslamicChronology in the list of included chronologies.

CARFAX/joda-time,CARFAX/joda-time,mohanaraosv/joda-time,tingting703/mp3_maven,Rok-Piltaver/joda-time,leadVisionary/joda-time,Alexey-N-Chernyshov/IU_AST_Mutation_Score,flightstats/joda-time,HossainKhademian/JodaTime,Shais14/joda-time,mosoft521/joda-time,Shais14/joda-time,tingting703/mp3_maven,JodaOrg/joda-time,flightstats/joda-time,Rok-Piltaver/joda-time,mohanaraosv/joda-time,rbible/joda-time,Guardiola31337/joda-time,tkawachi/joda-time,Guardiola31337/joda-time,lousama/joda-time,fengshao0907/joda-time,emopers/joda-time,mosoft521/joda-time,tkawachi/joda-time,lousama/joda-time,leadVisionary/joda-time,JodaOrg/joda-time,Alexey-N-Chernyshov/IU_AST_Mutation_Score,rbible/joda-time,fengshao0907/joda-time,emopers/joda-time