Highlight change in code view when settings are updated in the styles panel

[thatisrich]

What problem does this address?

With the code view panel introduced in #62, it can be quite difficult to see the effects within the code view of any changes made in the styles panel. For example, when changing the Site > Color > Background option, the relevant JSON update is quite far down in the code view panel.

This can lead to difficulties testing and also from the UX confirming that changes are actually being made.

What is your proposed solution?

• Slightly increase line height and container padding of the code view panel to improve reading legibility
• When updating any setting, highlight the relative line / lines within the code view

A quick screenshot showing how this could look

[g-elwell]

Closing as this was resolved by #88