Add missing v4.2 new color palettes (mauve, olive, mist, and taupe) to the reference section (#2457)

By the way, I noticed an inconsistency in the OKLCH color formatting
between the `docs/theme` and `docs/colors` pages. The `docs/theme` page
uses percentages for lightness values (e.g., `98.5%`), which matches the
format in `node_modules/tailwindcss/theme.css`. However, the reference
section in `docs/colors` uses decimals (e.g., `0.985`), even though the
color palette hovers and click-to-copy features on the same page use
percentages.

If you have a specific reason for this or prefer to keep it as-is, feel
free to merge directly.
Otherwise, if consistency is needed, let me know so I can update the
reference section in `docs/colors` to use percentages throughout.

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Co-authored-by: Robin Malfait <malfait.robin@gmail.com>

Author: muhammadcahya