Bump Razor to 10.0.0-preview.26066.2

[davidwengier]

Weekly bump

View Complete Diff of Changes

• [main] Source code updates from dotnet/dotnet (PR: #12698)
• Release a SyntaxListBuilder back to the pool. (PR: #12697)
• [main] Source code updates from dotnet/dotnet (PR: #12694)
• Take 2 to fix the image load regression (PR: #12683)
• Make rename integration test less flaky (PR: #12674)
• Move a couple statics that are highly contended on solution load to just be class members as their container is a singleton. (PR: #12679)
• Remove cohost feature flag, and hardcode to true (PR: #12669)
• [main] Update dependencies from dotnet/arcade (PR: #12672)
• Make ContainedLanguage import lazy (PR: #12670)
• Ignore case when parsing enum values in settings in VS Code (PR: #12667)