feat: add severed_relationships notification type

[poopsicles]

kind of a follow-up to #3077 and #3084, which added the console logging for unsupported noti types, but not the notification for severed_relationships.

it looks like:

compared to my instance's:

copied the language from upstream, I can probably just use their localisations too, right?

I'll probably expand the PR to add in moderation_warning if I can get a pic of how it should look like (or barring that, just copying upstream's impl)

(and maybe refactor annual_report to use localisations too?)

(also a bit unsure if i'm following the pluralisation guidelines, but hey, that's why it's a draft PR)

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[shuuji3]

Yes, using upstream localization is a smart idea.👍🏻

It's also nice to have moderation_warning. I did a quick search but couldn't find an actual screenshot (I only found a moderation-side UI: https://community.hachyderm.io/blog/2024/09/01/hachyderms-introduction-to-mastodon-moderation-the-report-feature-and-moderator-actions/). I think it's fine to assume UI and adjust for Elk from Mastodon's source code.

Those expansions can be included in this PR or separated if you'd like.

[shuuji3]

Probably not applicable in this case. Those are usually for short-string localization. But I'll review the guidelines later.

Also probably we'll need another type than object. Checking masto.js docs might help: https://neet.github.io/masto.js/

[shuuji3]

We can mark these words as translatable.

[shuuji3]

This is the icon for the moderation warning: https://icon-sets.iconify.design/mdi/?icon-filter=gavel

• https://github.com/mastodon/mastodon/blob/0db75588220719d5f812b33a3e45970118c6acb9/app/javascript/mastodon/features/notifications/components/moderation_warning.tsx#L70
• https://github.com/mastodon/mastodon/blob/0db75588220719d5f812b33a3e45970118c6acb9/app/javascript/mastodon/features/notifications/components/moderation_warning.tsx#L5

[shuuji3]

OK, I just fixed type check errors. Those are a bit complicated. One type of error requires yo update type definition in the upstream library, masto.js. The other one was due to a failure of type inference in Vue template. Anyway, you don't have to worry about them in this PR.