[PATCH] Add verbose comments to 'era' in ja_JP locale.

[Carlos O'Donell <codonell at redhat dot com>]

Rafal,

While reviewing DJ's new test I went through all the dates, years,
and names, and figured I'd put them into a verbose comment in ja_JP
to make this easier to maintain in the future.

What do you think of this for master?

8< --- 8< ---- 8<
---
 localedata/locales/ja_JP | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/localedata/locales/ja_JP b/localedata/locales/ja_JP
index 9bfbb2bb9b..74ef9e39f3 100644
--- a/localedata/locales/ja_JP
+++ b/localedata/locales/ja_JP
@@ -14946,6 +14946,29 @@ am_pm	"<U5348><U524D>";"<U5348><U5F8C>"
 
 t_fmt_ampm "%p%I<U6642>%M<U5206>%S<U79D2>"
 
+# The era names are laid out in groups of 2 to account for the desire
+# to avoid using '1' for the first era year.  Instead of 1 we use '元'
+# <U5143> or "gan" as the first era year.
+#
+# The following dates and their names are recorded below in descending
+# date order (note that '年' <U5E74> or "year" follows each date).
+#
+# Offset: Start date:	End date:	Era name:	Using "gan":
+# (Y)     (YYYY-MM-DD)
+# 2       1990-01-01	+*		平成 (Heisei)	No
+# 1       1989-01-08	1989-12-31	平成 (Heisei)	Yes
+# 2       1927-01-01	1989-01-07	昭和 (Shōwa)	No
+# 1       1926-12-25	1926-12-31	昭和 (Shōwa)	Yes
+# 2       1913-01-01	1926-12-24	大正 (Taishō)	No
+# 1       1912-07-30	1912-12-31	大正 (Taishō)	Yes
+# 6       1873-01-01	1912-07-29	明治 (Meiji)	No
+# 1       0001-01-01	1872-12-31	西暦 (C.E)	No
+# 1       -0000-12-31	-*		紀元前 (B.C.E.)	No
+#
+# Note:
+# - The last entry 紀元前 means pre-era/B.C./B.C.E.
+# - The second-to-last entry 西暦 means C.E.
+#
 era	"+:2:1990//01//01:+*:<U5E73><U6210>:%EC%Ey<U5E74>";/
 	"+:1:1989//01//08:1989//12//31:<U5E73><U6210>:%EC<U5143><U5E74>";/
 	"+:2:1927//01//01:1989//01//07:<U662D><U548C>:%EC%Ey<U5E74>";/
--
2.20.1