Add items-first-baseline and items-last-baseline utilities - v3

[hbendev]

This PR adds the items-first-baseline and items-last-baseline utility classes that can control baseline-position for the align-items property.

Browser support:

• MDN: https://developer.mozilla.org/en-US/docs/Web/CSS/align-items#browser_compatibility
• Can I use first baseline: https://caniuse.com/?search=align%20items%3A%20first%20baseline
• Can I use last baseline: https://caniuse.com/?search=align%20items%3A%20last%20baseline

The feature were requested multiple times:

• Support additional align-items #13518
• Add support for items-last-baseline #12406
• Add items-last-baseline #11623
• First/last baseline utilities #4855

A special plugin in tailwind.config.js can be used as an existing workaround:

plugin(function extendItemsBaselineUtilities({ addUtilities }) {
  // https://developer.mozilla.org/en-US/docs/Web/CSS/align-items#start
  // https://developer.mozilla.org/en-US/docs/Web/CSS/align-items#end
  addUtilities({
    ".items-first-baseline": { "align-items": "first baseline" },
    ".items-last-baseline": { "align-items": "last baseline" },
  });
});

V4 counterpart PR: #13888

[RobinMalfait]

Hey!

Thanks for this PR, but since Tailwind CSS v4 is out we won't be adding new features to v3. If you want this feature to v4, feel free to contribute against the next branch (at the time of writing this).

If you want to add this to your own v4 projects today, you can use:

@import "tailwindcss";

@utility items-first-baseline {
  align-items: first baseline;
}

@utility items-last-baseline {
  align-items: last baseline;
}

Example Play: https://play.tailwindcss.com/AMP4hBxpCX?file=css

Thanks again for this PR, appreciate it!

[hbendev]

@RobinMalfait v4 counterpart PR: #13888 :)

But I like the example already so much! Thanks, and congrats on the new major version!