Enlarge header icons

[illright]

Description

Related to #1701, but not explicitly proposed there. The original proposal suggests to increase the space between the social icons, but I believe the icons themselves should be larger too.

This PR changes the appearance of social icons and the icons in language/theme selects to be larger. It also increases the touch area of the social icons to align it with the touch area of selects (~44.5px on desktop, ~48px on mobile). Finally, it marginally increases the space between the icon and the label, just something that's been bugging me visually a little bit.

Screenshots

Desktop (light)

Before	After

Desktop (dark)

Before	After

Mobile (light)

Before	After

Mobile (dark)

Before	After

[changeset-bot]

🦋 Changeset detected

Latest commit: 928686f

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@astrojs/starlight	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[netlify]

✅ Deploy Preview for astro-starlight ready!

Name	Link
🔨 Latest commit	928686f
🔍 Latest deploy log	https://app.netlify.com/sites/astro-starlight/deploys/675492ec2c3bd80008dc4a84
😎 Deploy Preview	https://deploy-preview-2661--astro-starlight.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 100 (no change from production) Accessibility: 100 (no change from production) Best Practices: 100 (no change from production) SEO: 100 (no change from production) PWA: - View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify site configuration.