Fix on-type and code action formatting on Razor explicit statements

[davidwengier]

Noticed this today while testing something completely unrelated.

Review commit at a time if you want to see the current behaviour versus the fix, but its not a huge PR so up to you whether you care :)

Microsoft Reviewers: Open in CodeFlow

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[Copilot]

Pull request overview

This PR adjusts Razor’s C# on-type formatting indentation logic to special-case explicit statement delimiters (@{ ... }) so they don’t get incorrectly re-indented based on C# source mappings, and adds regression coverage across on-type formatting, document formatting, and code-action formatting paths.

Changes:

• Update CSharpOnTypeFormattingPass to detect explicit statement delimiters and apply only Razor/HTML indentation (skipping C# source-mapped indentation).
• Add an on-type formatting regression test covering } formatting within an explicit statement block.
• Add regression tests ensuring document formatting and the Invert If code action preserve/correct explicit-statement indentation.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
src/Razor/src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.UnitTests/Cohost/Formatting/OnTypeFormattingTest.cs	Adds on-type formatting regression test for explicit statement scenarios.
src/Razor/src/Razor/test/Microsoft.CodeAnalysis.Razor.CohostingShared.UnitTests/Formatting/DocumentFormattingTest.cs	Adds document-formatting regression tests covering mis-indented explicit statement opening braces.
src/Razor/src/Razor/test/Microsoft.CodeAnalysis.Razor.CohostingShared.UnitTests/CodeActions/CSharpCodeActionTests.cs	Adds code-action regression test ensuring Invert If produces correctly formatted output within explicit statements.
src/Razor/src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/Passes/CSharpOnTypeFormattingPass.cs	Implements explicit-statement delimiter indentation handling by bypassing C# source-mapped indentation.