README.md does not link to correct documentation item for BitHelper

### Describe the bug

I just read the new [blog post](https://devblogs.microsoft.com/dotnet/announcing-the-dotnet-community-toolkit-800/) about CommunityToolkit 8.0 being released (congrats!) and followed the link that brought me here to the [CommunityToolkit/dotnet](https://github.com/CommunityToolkit/dotnet) repo. The README mentions a few things about the CommunityToolkit packages but thing I wanted to read more about which was BitHelper.

Clicking that link actually takes me to [Span2D](https://docs.microsoft.com/en-au/windows/communitytoolkit/high-performance/span2d).

I was able to find some documentation over [here](https://docs.microsoft.com/en-us/dotnet/api/microsoft.toolkit.highperformance.helpers.bithelper?view=win-comm-toolkit-dotnet-7.0) but I am unsure if anything changed here from when it changed from MicrosoftToolkit 7 to CommunityToolkit 8.

The README also says 7.1.2 is the latest version, but 8 is. Is there an updated README that didn't make it through which is meant to link to the CommunityToolkit specific documentation?

### Regression

_No response_

### Steps to reproduce

```text
Open this repo, scroll down to where it mentions the CommunityToolkit.* packages, click BitHelper link.
```

### Expected behavior

Be able to read about BitHelper in CommunityToolkit 8.

### Screenshots

_No response_

### IDE and version

Other

### IDE version

_No response_

### Nuget packages

- [ ] CommunityToolkit.Common
- [ ] CommunityToolkit.Diagnostics
- [ ] CommunityToolkit.HighPerformance
- [ ] CommunityToolkit.Mvvm (aka MVVM Toolkit)

### Nuget package version(s)

N/A

### Additional context

_No response_

### Help us help you

No, just wanted to report this