Fix menu localization not updated for "Open Tab..." item (#12993)

THe menu item "Open Tab..." was changed to "Open &Tab..." in #12895 but
localization files were not updated. Update it here.

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/lang/menu_ja_jp.utf-8.vim b/runtime/lang/menu_ja_jp.utf-8.vim
index b3a8d64..70db44a 100644
--- a/runtime/lang/menu_ja_jp.utf-8.vim
+++ b/runtime/lang/menu_ja_jp.utf-8.vim
@@ -39,7 +39,7 @@
 menutrans &File				ファイル(&F)
 menutrans &Open\.\.\.<Tab>:e		開く(&O)\.\.\.<Tab>:e
 menutrans Sp&lit-Open\.\.\.<Tab>:sp	分割して開く(&L)\.\.\.<Tab>:sp
-menutrans Open\ Tab\.\.\.<Tab>:tabnew	タブページで開く<Tab>:tabnew
+menutrans Open\ &Tab\.\.\.<Tab>:tabnew	タブページで開く<Tab>:tabnew
 menutrans &New<Tab>:enew		新規作成(&N)<Tab>:enew
 menutrans &Close<Tab>:close		閉じる(&C)<Tab>:close
 menutrans &Save<Tab>:w			保存(&S)<Tab>:w