TUNU0001 code fixer corrupts code when #region directive follows a comment

[thomhurst]

Description

The TUNU0001 NUnit migration code fixer corrupts code when a #region directive follows a single-line comment. The comment and #region directive are merged onto the same line, causing CS1028 syntax errors.

Reproduction Steps

1. Create a test file with this pattern:

using NUnit.Framework;

[TestFixture]
public class MyTests
{
    // Some comment
    #region My Region
    
    [Test]
    public void TestMethod()
    {
    }

    #endregion
}

2. Run the TUNU0001 code fixer

Expected Behavior

The code should remain valid with proper formatting:

public class MyTests
{
    // Some comment
    #region My Region
    
    [Test]
    public async Task TestMethod()
    {
    }

    #endregion
}

Actual Behavior

The comment and #region are merged into a single line:

public class MyTests
{
    // Some comment			#region My Region
    
    [Test]
    public async Task TestMethod()
    {
    }

    #endregion
}

This causes:

error CS1028: Unexpected preprocessor directive

Environment

• TUnit version: 1.11.64
• .NET SDK: 10.0.102

Tests should be added to verify the code fixer correctly handles #region directives near comments.

[claude]

This appears to be related to #4481, which reports the same bug in the TUXU0001 code fixer. Both code fixers seem to have the same underlying issue with merging comment lines with preprocessor directives (#region, #if, etc.).