* matrix: send the display name (the nickname in matrix parlance) instead of the user name
There is also the option UseUserName (already in use by the discord bridge) to turn back to the old behavior.
* matrix: update displayNames on join events
* matrix: introduce a helper.go file to keep matrix.go size reasonable
When using the webhook, the previous method to edit a message was to
delete the old one via the classical API, and to create a new message
via the webhook. While this works, this means that editing "old" messages
lead to a mess where the chronological order is no longer respected.
This uses an hidden API explained in https://support.discord.com/hc/en-us/community/posts/360034557771
to achieve a proper edition using the webhook API.
The obvious downside of this approach is that since it is an
undocumented API for now, so there is no stability guarantee :/
This includes at least c-source-files, cpp-source-files,
markdown-files, Rust-files, and plaintext files.
We already allow uploading arbitrary executables. (And javascript-files,
coincidentally.) Not permitting these other text files would be highly unexpected.
The current way to get the correct JID of a WhatsApp group is to dump all JIDs to the log and grab the right one. This is working for for groups fine but not for broadcast, as they are not print out.
According to https://www.npmjs.com/package/@noamalffasy/js-whatsapp we have these possibilities:
* Chats: `[country code][phone number]@s.whatsapp.net`
* Groups: `[country code][phone number of creator]-[timestamp of group creation]@g.us`
* Broadcast Channels: `[timestamp of group creation]@broadcast`
But the bridge does currently interprets (and prints) the only second option.
