RFR 9 8062513: doclint warnings in HijrahChronology

[roger riggs]

Please review a correction to address a doclint warning in HijrahChronology.

Webrev:
   http://cr.openjdk.java.net/~rriggs/webrev-doclint-8062513/

Issue:
   8062513: doclint warnings in HijrahChronology

Thanks, Roger