Please provide example for combining raw string literals with interpolated string

### Type of issue

Missing information

### Description

I keep forgetting how to combine raw string literal with interpolated strings which I use, but obviously not use enough apperantly, when testing and building json objects.
And my issue is the text here is just not clear enough for me to understand I both have to use multiple $ characters _and_ multiple { and } so it would be very beneficial with an actual example in the documentation, something like 🙂

```c#
string jsonPayload = $$"""
{
"firstName": {{firstname}},
"lastName": "{{lastname}}"
}
""";
```

[Enter feedback here]
Raw string literals can also be combined with [interpolated strings](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/interpolated#interpolated-raw-string-literals) to embed the { and } characters in the output string. You use multiple $ characters in an interpolated raw string literal to embed { and } characters in the output string without escaping them.

### Page URL

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/raw-string

### Content source URL

https://github.com/dotnet/docs/blob/main/docs/csharp/language-reference/tokens/raw-string.md

### Document Version Independent Id

5737c986-9b06-9444-f7bc-893607d390d7

### Article author

@BillWagner

### Metadata

* ID: 62bd57d5-0e7d-4355-0689-4b6b90ab4057
* Service: **dotnet-csharp**
* Sub-service: **lang-reference**

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