Need to document EmitCompilerGeneratedFiles for "No ModelReaderWriterTypeBuilder found for [Name]"

[cataggar]

The documentation linked to https://aka.ms/no-modelreaderwritertypebuilder-found is not quite correct.

azure-sdk-for-net/sdk/core/System.ClientModel/src/docs/ModelReaderWriterContext.md

Lines 101 to 112 in 6fe19ec

	## No ModelReaderWriterTypeBuilder found
	If you encounter an error message like "No ModelReaderWriterTypeBuilder found for [Name]", it means that ModelReaderWriter attempted to read or write
	a type for which no appropriate ModelReaderWriterTypeBuilder exists in your context.
	Troubleshooting Steps
	1. Ensure you have the System.ClientModel.SourceGeneration analyzers installed. In general simply adding
	a package reference to System.ClientModel will do this but you can verify in your project dependencies that you see the reference.
	2. Ensure you have a public partial class that inherits from [ModelReaderWriterContext](#context-class).
	3. If the type is one of the [supported collections](#supported-collection-types) then add the [ModelReaderWriterBuildableAttribute](#modelreaderwriterbuildableattribute) for your missing type.
	4. If the type is not one of the [supported collections](#supported-collection-types) then add a [custom type builder](#custom-type-builders) for your missing type.

Instead, I had to add this line:

azure-sdk-for-net/sdk/core/System.ClientModel/tests/gen/System.ClientModel.SourceGeneration.Tests.csproj

Line 7 in 6fe19ec

<EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles>

Files then generated correctly:

I'm not sure if changes for this issues are related:

• [FEATURE REQ] Allow disabling of code generation when importing System.ClientModel #49995