doom-nova visual modifications

[donniebreve]

Changes some of the faces for the doom-nova theme.

1. The inactive mode line color is lightened to provide a separation between horizontal splits
2. The active mode line color is darkened (preference only)
3. The current vertico selection is darkened so text is readable

Changes:

To:

• [x] I searched the issue tracker and this hasn't been PRed before.
• [x] My changes are not on the do-not-PR list for this project.
• [x] My commits conform to the git conventions.
• [x] My changes are visual; I've included before and after screenshots.