When an absolute link is missing the leading slash (it starts with
"docs/foo" instead of "/docs/foo/"), print a more specific error instead
of the generic catch-all warning.
Without the leading slash, these are treated as relative paths and so
lead to non-existing pages.
Also, while we're at it, fix the instance it detects.
We have the translation guideline as [1], and that contains what are
valid Japanese words for the corresponding English words.
This adds a script to verify those words based on the guideline.
[1]: https://kubernetes.io/ja/docs/contribute/localization/
* Add a helper script for localization
The script generates a report of outdated contents in
`content/<l10n-lang>` directory by comparing two l10n
team milestone branches.
* Add description for scripts/diff_l10n_branches.py