Theme to define separate background for git gutter

[narqo]

Check for existing issues

• [X] Completed

Describe the feature

I propose expanding the current object model for Zed's theme, allowing to define background colours for git gutter. Right now, the colours defined with created, modified and deleted are used as both text colours for the workspace file names, and background of git gutter. I find this unfortunate, at least with light schemas. A darker colour should be used for text, but a lighter variant of this colour for background. Other, the gutter becomes too visually heavy, and grabs too much of attention from the code.

If applicable, add mockups / screenshots to help present your vision of the feature

No response

[narqo]

For the reference, this is how it's solved in Goland IDE

Note on the screenshot:

• the gutter uses pastel colours to show modified sections of the code
• the title uses bright blue colour for the text (it's not shown on the screenshot but this same one is used in the project navigator)