Thread.FreeNamedDataSlot code examples are not contain any calls to the desired method

### Type of issue

Missing information

### Description

Example code section for method reference: `Thread.FreeNamedDataSlot()` doesn't contain any calls of the `FreeNamedDataSlot()`, in fact code examples are equal to `GetNamedDataSlot() ` & `AllocateDataSlot() ` code examples.
Kindly propose to add example showcasing `FreeNamedDataSlot()` usage

### Page URL

https://learn.microsoft.com/en-us/dotnet/api/system.threading.thread.freenameddataslot?view=net-8.0

### Content source URL

https://github.com/dotnet/dotnet-api-docs/blob/main/xml/System.Threading/Thread.xml

### Document Version Independent Id

9c8d22a1-0c8c-29ee-3624-21d40a10f852

### Article author

@dotnet-bot