The HTML archives are updating again

[Daniel Shahaf <d.s@daniel.shahaf.name>]

The HTML archives are now again getting updated with new posts:

https://www.zsh.org/mla/
https://www.zsh.org/mla/announce/
https://www.zsh.org/mla/users/2021/
https://www.zsh.org/mla/workers/2021/

Old links should continue to work, including links to attachments.

Known issues:

- Messages between last August and yesterday also two Archived-At
  headers, and the URL in the second one just gives an error.  The URL
  will no longer be added to new messages.

- As part of the migration, the X-Seq values for both -users@ and -workers@
  were bumped by 1000.  The gaps are 46290→47291 and 25012→26013.

New bells and whistles:

- The HTML form of zsh-announce@'s archive.

- The list of headers rendered in a message page was trimmed, and "Cc"
  was moved up.

- The threaded view won't flatten threads at some fixed maximum depth.

- Syntactic sugar for the "linking to a message by X-Seq" functionality:
  https://zsh.org/workers/42

- Archived-At headers using the syntactic sugar.

- The list of years on /mla/index.html will be automatically updated.

- A "Send me my patches' X-Seq values by return post" bot, hard-wired to
  only respond to Mikael.

Please report any issues.

Apologies for the length of the downtime.

The raw rfc822 archives, available over https:// and rsync://, have been
continuously available and up-to-date throughout the downtime.

Cheers,

Daniel