Setting RenderOptions.ClearTypeHint to Enabled doesn't render text with ClearType

### Description

According to the sample provided at https://learn.microsoft.com/en-us/dotnet/api/system.windows.media.renderoptions.cleartypehint, the third line should be rendered with ClearType.

### Reproduction Steps

Create a WPF application with the following XAML window:
```xaml

```

### Expected behavior

The third line should be rendered with ClearType.

### Actual behavior

The third line is rendered with grayscale:


Zoomed view:

### Regression?

_No response_

### Known Workarounds

_No response_

### Impact

_No response_

### Configuration

Tested with .NET Framework 4.0 up to .NET 8.0.0-rc.2 under Windows 10 22H2.

### Other information

I don't know if it is a bug in WPF, or that it is meant to be rendered with grayscale.
If the latter is the case, the documentation (and the sample code) should be updated/clarified.