fix: correct typos and improve clarity in user experience guides

[chanmilee-fe]

Summary

Fix several typos across guides/user-experience/ to improve clarity and readability. No behavioral or guidance changes.

Affected guides:

• design-token-reactivity — precendence → precedence
• improve-text-layout-and-legibility — duplicate and and → and
• navigation-drawer — achive → achieve, seprarate → separate
• scroll-progress-indicator — neareast → nearest
• scroll-snap-state-sync — aboce → above
• search-hidden-content — accessiblity → accessibility
• shrinking-header-on-scroll — headder → header (heading)

Test plan

• pnpm preflight (w/ node v24)
• Visual diff review of all 7 guides

[rviscomi]

Thanks @chanmilee-fe! These guides have moved recently, which created some merge conflicts. Are you able to sync and resolve those?

[chanmilee-fe]

Thanks @chanmilee-fe! These guides have moved recently, which created some merge conflicts. Are you able to sync and resolve those?

Thanks for the heads-up! I've rebased this branch onto the latest main. The guides I edited had been moved into new category folders (css/, ui-atoms/, ui-behaviors/, ui-components/, visual-design/), which is what caused the merge conflicts. After rebasing, the typo fixes now apply cleanly to the files at their new locations, so the conflicts are resolved and the PR is mergeable again. The diff is unchanged — still just the 8 typo/wording fixes. 🙂

[LeaVerou]

Thank you!