Reference beta by version rather than date

Since[^1] this guide has been written https://github.com/rust-lang/rust-forge/blob/c78057351dcfa27af64da7658653c4e0b7db70d3/src/release/crater.md?plain=1#L16-L18 It is now also possible to specify beta version by their version instead of just by date i.e. 1.75.0-beta for latest beta of 1.75.0 or 1.75.0-beta.1 for the first beta release of 1.75.0. So would it make sense to simplify this guide to ```md $STABLE is e.g. `1.80.0` (the stable release) and $BETA is `1.81.0-beta.1`. ``` [^1]: the release process started creating the necessary channel files with [beta-1.75.0-beta.1](https://static.rust-lang.org/dist/channel-rust-1.75.0-beta.1.toml) and rustup gained to capability to use those in rustup-1.28.0