Rename a language, a whole interface from ?lang=, and accented anchors

Added

PATCH /orgs/{orgId}/spaces/{spaceId}/docs/locales/{code} with { "label": "…" } renames a language in the reader's switcher. {code} may be default, which relabels the source language — "Original" until now, with no way to change it. Answers the full locales list, like POST and DELETE.

Fixed

• ?lang= now translates the whole page, not only the parts rendered in the browser. "On this page", "Skip to content", "Updated", previous/next, the status pill and the reader 404 stayed English unless the forumulate_lang cookie was set.

• A translation sets the interface language when the reader has chosen none: ?locale=es frames a Spanish page in Spanish labels.

• Redirects keep the query string. /docs?locale=es answered /docs/introduction with the locale dropped; the same was true of renamed blog posts, author and series pages, and migrated forum links.

• Heading anchors fold accents instead of deleting the letter: "Caché con ETags" is #cache-con-etags (was #cach-con-etags). The old id still lands on the heading.

• Reader labels that were hard-coded English — comment threads, subscribe buttons, the private-docs sign-in, and more — now follow the reader's language.

See Authoring reference → Locales.