DIY Make language underlines less colorful

This is one of our practical examples to override the semantic colors of the Modus themes (Stylistic variants using palette overrides). Here we show how to affect the color of the underlines that are used by code linters and prose spell checkers.

;; Make the underlines less intense
(setq modus-themes-common-palette-overrides
      '((underline-err red-faint)
        (underline-warning yellow-faint)
        (underline-note cyan-faint)))

;; Change the color-coding of the underlines
(setq modus-themes-common-palette-overrides
      '((underline-err yellow-intense)
        (underline-warning magenta-intense)
        (underline-note green-intense)))

Reload the theme for changes to take effect.