[DataGrid] Add HeaderCellTitleTemplate to ColumnBase

[philliphoff]

Pull Request

📖 Description

Adds a HeaderCellTitleTemplate property to the ColumnBase type of FluentDataGrid. This allows users to customize the column header text beyond just text, but without having to take ownership of the resize/sort/filter column options UX required when using the HeaderCellTemplate property. If not set, then the column Title is displayed as plain text as before.

A new section of the guide/docs site was added to demonstrate this new feature.

🎫 Issues

• feat: add HeaderCellTitleTemplate to FluentDataGrid columns #3850

👩‍💻 Reviewer Notes

📑 Test Plan

There doesn't seem to be any existing unit/integration tests related to FluentDataGrid header generation, so testing of this change has been ad-hoc, mostly via the generated docs page.

✅ Checklist

General

• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

Component-specific

• I have added a new component
• I have added Unit Tests for my new component
• I have modified an existing component
• I have validated the Unit Tests for an existing component

⏭ Next Steps

[vnbaaij]

Nice addition. Thanks!