Optional args for holiday-greek-orthodox-easter

* etc/NEWS: Document this.
* lisp/calendar/holidays.el (holiday-greek-orthodox-easter):
Add optional args N and STRING, mimicking the API and code of
‘holiday-easter-etc’.  From suggestion by Foivos S. Zakkak (Bug#21256).

1 files changed, 3 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 0a33a6ef3ee..3ec16f54458 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -552,6 +552,9 @@ The option customizes which day headers receive the
 `calendar-weekend-header' face.
 
 ---
+*** New optional args N and STRING for ‘holiday-greek-orthodox-easter’.
+
+---
 *** Many items obsolete since at least version 23.1 have been removed.
 The majority were function/variable/face aliases, too numerous to list here.
 The remainder were: