Move documentation to docs.astral.sh/ruff (#7419)

## Summary

We're planning to move the documentation from
[https://beta.ruff.rs/docs](https://beta.ruff.rs/docs) to
[https://docs.astral.sh/ruff](https://docs.astral.sh/ruff), for a few
reasons:

1. We want to remove the `beta` from the domain, as Ruff is no longer
considered beta software.
2. We want to migrate to a structure that could accommodate multiple
future tools living under one domain.

The docs are actually already live at
[https://docs.astral.sh/ruff](https://docs.astral.sh/ruff), but later
today, I'll add a permanent redirect from the previous to the new
domain. **All existing links will continue to work, now and in
perpetuity.**

This PR contains the code changes necessary for the updated
documentation. As part of this effort, I moved the playground and
documentation from my personal Cloudflare account to our team Cloudflare
account (hence the new `--project-name` references). After merging, I'll
also update the secrets on this repo.

crates/ruff_workspace/src/options.rs

@@ -1994,7 +1994,7 @@ pub struct PycodestyleOptions {
     /// documentation (`W505`), including standalone comments. By default,
     /// this is set to null which disables reporting violations.
     ///
-    /// See the [`doc-line-too-long`](https://beta.ruff.rs/docs/rules/doc-line-too-long/) rule for more information.
+    /// See the [`doc-line-too-long`](https://docs.astral.sh/ruff/rules/doc-line-too-long/) rule for more information.
     pub max_doc_length: Option<LineLength>,
     #[option(
         default = "false",