Backport XML doc comments for DispatchProxy from dotnet-api-docs

[Copilot]

Fixes dotnet/dotnet-api-docs#12316.

Description

Backports XML documentation for DispatchProxy from dotnet-api-docs.

Changes

• Updated summaries and parameter descriptions to match dotnet-api-docs
• Used <see langword="null" /> instead of <c>null</c> for keyword references
• Formatted exception documentation with <para> tags for multi-condition cases
• Fixed exception documentation to accurately reflect actual validation logic:
  • Create<T, TProxy>: Changed "T is a class" to "T is not an interface type" and added "abstract" condition for TProxy
  • Create(Type, Type): Changed "interfaceType is a class" to "interfaceType is not an interface type" and added "abstract" condition for proxyType
• Fixed grammar error: Create(Type, Type) exception docs stated proxy type throws when it "has" a parameterless constructor; corrected to "does not have" (matches code behavior requiring DynamicallyAccessedMemberTypes.PublicParameterlessConstructor)
• Added XML documentation for the protected constructor (was missing in dotnet-api-docs)
• Removed <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile> from the project file to enable automatic XML documentation file generation

Similar to PR #124227.

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[gewarren]

@copilot Please also update the .csproj file for this assembly to remove <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>.

[gewarren]

@copilot Please also update the .csproj file for this assembly to remove <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>.

[Copilot]

@copilot Please also update the .csproj file for this assembly to remove <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>.

Done in 086f322.

@copilot Please also update the .csproj file for this assembly to remove <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>.

Done in 086f322.

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[Copilot]

Pull request overview

Backports and modernizes XML documentation for System.Reflection.DispatchProxy to align with dotnet-api-docs, and adjusts the project to allow compiler-generated XML doc output.

Changes:

• Updated DispatchProxy XML docs (summaries, params/returns, and exception docs), including using <see langword="null" />.
• Reformatted multi-condition exception documentation using <para> blocks.
• Removed <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile> from the project file to enable compiler XML documentation generation.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/libraries/System.Reflection.DispatchProxy/src/System/Reflection/DispatchProxy.cs	Doc updates for summaries/params/returns and exception documentation on Invoke and Create overloads.
src/libraries/System.Reflection.DispatchProxy/src/System.Reflection.DispatchProxy.csproj	Enables compiler-generated XML doc file by removing an overriding property.