Add code fixers for MA0182 (Avoid unused internal types)

[Copilot]

• Create AvoidUnusedInternalTypesFixer with two code fix actions:
  • Remove type declaration - ✅ Removes document from solution when it's the only type (preserves files with assembly attributes)
  • Add DynamicallyAccessedMembers attribute - ✅ Working
• Add comprehensive tests for both code fixers:
  • Test removing single type from file - ✅
  • Test removing type when multiple types exist in file - ✅
  • Test removing nested type - ✅
  • Test removing type with usings - ✅
  • Test removing type with namespace - ✅
  • Test removing type (record struct) - ✅
  • Test removing first of two unused types - ✅
  • Test removing type with assembly attribute - ✅
  • Test adding DynamicallyAccessedMembers attribute to class - ✅
  • Test adding DynamicallyAccessedMembers attribute to struct - ✅
  • Test adding DynamicallyAccessedMembers attribute to record - ✅
  • Test adding DynamicallyAccessedMembers attribute with existing attributes - ✅
• Build and validate the changes - All 110 tests passing
• Update markdown documentation
• Address review feedback:
  • Changed to Solution-based approach
  • Use RemoveDocument instead of creating empty file
  • Preserve files with assembly attributes

Original prompt

Can you add 2 code fixers for MA0182:

• Remove the type (and the file if there is no other type in the file)
• Add DynamicallyAccessMembers attribute

Be sure to include as many tests as needed

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[meziantou]

@copilot I'm not sure this works. I think you need to use an overload of CodeAction.Create that uses a solution

[Copilot]

Fixed in commit b59f55d. Changed RemoveTypeDeclaration to return Task<Solution> instead of Task<Document>, and now using SyntaxFactory.CompilationUnit() to create an empty file when removing the only type. All 109 tests passing.

[meziantou]

@copilot Shouldn't this create a new solution without the document?

[Copilot]

Fixed in commit c16d1f0. Now using solution.RemoveDocument(document.Id) to remove the document from the solution when it contains only one unused type. Updated test framework to handle document removal. All 109 tests passing.

[meziantou]

@copilot I think it should also test for assembly attribute [assembly: xyz]. In this case, it shouldn't remove the file. Please add a test.

[Copilot]

Fixed in commit 2e8a1d4. Added check for compilationUnit.AttributeLists.Count == 0 to preserve files with assembly attributes. Added test CodeFix_RemoveType_WithAssemblyAttribute to verify the behavior. All 110 tests passing.