Issue 9 colore view only

[qclayssen]

This Pull Request aims to enhance the tidySingleCellExperiment package by visually distinguishing view-only columns. The goal was to color the headers of these columns for easy identification. The main update is in the print.SingleCellExperiment function.

Key Points:

• Attempt to modify header coloring for view-only columns.
• Update in the print.SingleCellExperiment function.

Challenges:

• The header coloring feature is not fully functional. Attempts to color the headers result in outputs where the color codes are not properly rendered.

`\033[31mPC_1\033[39m`

Note: The feature requires further development and debugging. Contributions and suggestions to resolve this issue are welcome.

Link to Issue: [Issue Number 9]