The xorm `Sync2` has already been deprecated in favor of `Sync`,
so let's do the same inside the Gitea codebase.
Command used to replace everything:
```sh
for i in $(ag Sync2 --files-with-matches); do vim $i -c ':%sno/Sync2/Sync/g' -c ':wq'; done
```
This PR adds our matrix space to the support options and alphabetizes
the list.
I also considered adding our Mastodon, however that isn't as suitable as
the other options because it's just whoever has access to the account vs
a community chat/forum.
---------
Signed-off-by: jolheiser <john.olheiser@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>
This PR cleans up the docs in a way to make them simpler to ingest by
our [docs repo](https://gitea.com/gitea/gitea-docusaurus).
1. It includes all of the sed invocations our ingestion did, removing
the need to do it at build time.
2. It replaces the shortcode variable replacement method with
`@variable@` style, simply for easier sed invocations when required.
3. It removes unused files and moves the docs up a level as cleanup.
---------
Signed-off-by: jolheiser <john.olheiser@gmail.com>
