feat: Add helper comments for extended-colors when previewing.

[LoTwT]

Clear and concise description of the problem

I extend a color in the uno.config.ts and use it in my project. When previewing, it displays the color in RGB, the unocss generated results. When developing, I want to check the color to match the figma which provides the HEX instead of RGB.

// uno.config.ts
export default defineConfig({
  theme: {
    colors: {
      "my-color": "#0070E0",
    },
  },
})

Suggested solution

Could it add some helper comments like above?

Alternative

Additional context

Same proposal in the hyoban/tailwindcss-classname-highlight.

No response

Validations

• Read the Contributing Guidelines.
• Read the README.md of using the package.
• Already used the Interactive Docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.