Add japanese translation files (#4490)

* Add japanese translation

* Add translations

* rename

* Add fallback to match Accept-Language to the UNIX locale.

* Fix supported_languages

* Do not add if exists

* Do not add en

* Fix translation

* Add translation

* Fix typo

* Update notebook/i18n/ja_JP/LC_MESSAGES/nbjs.po

Co-Authored-By: mattn <[email protected]>

* Update notebook/i18n/ja_JP/LC_MESSAGES/nbjs.po

Co-Authored-By: mattn <[email protected]>

* Update notebook/i18n/ja_JP/LC_MESSAGES/nbjs.po

Co-Authored-By: mattn <[email protected]>

* Update notebook/i18n/ja_JP/LC_MESSAGES/nbjs.po

Co-Authored-By: mattn <[email protected]>

* Update notebook/i18n/ja_JP/LC_MESSAGES/nbjs.po

Co-Authored-By: mattn <[email protected]>

* Update notebook/i18n/ja_JP/LC_MESSAGES/nbui.po

Co-Authored-By: mattn <[email protected]>

* Update notebook/i18n/ja_JP/LC_MESSAGES/nbjs.po

Co-Authored-By: mattn <[email protected]>

* Update notebook/i18n/ja_JP/LC_MESSAGES/notebook.po

Co-Authored-By: mattn <[email protected]>

* Fixes some pointed by review

* Add translation

Co-authored-by: Kenichi Ito <[email protected]>

Author: mattn

notebook/i18n/__init__.py

@@ -45,6 +45,10 @@ def parse_accept_lang_header(accept_lang):
         if qvalue == 0:
             continue  # 0 means not accepted
         by_q[qvalue].append(lang)
+        if '_' in lang:
+            short = lang.split('_')[0]
+            if short != 'en':
+                by_q[qvalue].append(short)
 
     res = []
     for qvalue, langs in sorted(by_q.items()):