Details missing for defaults of build configurations other than Debug/Release

The default values for "DebugType" and "Optimize" are documented for the *Release* and *Debug* configurations. It's not documented what the default is for custom configurations.

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#### Document Details

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* ID: 35131307-8d1c-2800-e84a-6179d740982f
* Version Independent ID: 7599b464-9928-88bc-fec1-704ce691b344
* Content: [C# Compiler Options - code generation options](https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-options/code-generation)
* Content Source: [docs/csharp/language-reference/compiler-options/code-generation.md](https://github.com/dotnet/docs/blob/main/docs/csharp/language-reference/compiler-options/code-generation.md)
* Product: **dotnet-csharp**
* Technology: **csharp-language-reference**
* GitHub Login: @BillWagner
* Microsoft Alias: **wiwagn**