Add commit hash

Author: chalin

content/ja/docs/specs/_index.md

@@ -6,6 +6,7 @@ weight: 960
 # _build: { render: link }
 redirect: /docs/specs # TODO: this will need to be /en/...
 redirects: [{ from: '*', to: ':splat' }]
+default_lang_commit: 3b44fbfa49ced919daea01123abfaed836d2d0ec
 ---
 
 Netlify redirect target: [{{% param "title" %}}]({{% param "redirect" %}}).