refactor: remove some useless code

[lex111]

Motivation

Just a little cleaning up of codebase.

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

Preview

Related PRs

(If this PR adds or changes functionality, please take some time to update the docs at https://github.com/facebook/docusaurus, and link to your PR here.)

[netlify]

✔️ [V2]

🔨 Explore the source changes: 7c33f2c

🔍 Inspect the deploy log: https://app.netlify.com/sites/docusaurus-2/deploys/61bba8027fc74f000741b6e2

😎 Browse the preview: https://deploy-preview-6118--docusaurus-2.netlify.app

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟠 Performance	89
🟢 Accessibility	98
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-6118--docusaurus-2.netlify.app/

[github-actions]

Size Change: -27 B (0%)

Total Size: 652 kB

ℹ️ View Unchanged

Filename	Size	Change
website/.docusaurus/globalData.json	37.8 kB	0 B
website/build/assets/css/styles.********.css	101 kB	0 B
website/build/assets/js/main.********.js	484 kB	-27 B (0%)
website/build/index.html	29.3 kB	0 B

_{compressed-size-action}

[Josh-Cena]

Just wondering: where was useLocationHash used previously? Could it actually be useful in some cases and be added to theme-common?

[lex111]

Don't think we need this hook, it's too specific, usually useLocationChange covers all needs.