fix(core): fix serve workaround regexp

[slorber]

Motivation

Handle this comment:
#10142 (review)

Test Plan

local

[netlify]

✅ [V2]

Name	Link
🔨 Latest commit	de49a06
🔍 Latest deploy log	https://app.netlify.com/sites/docusaurus-2/deploys/664632f5655d290008e845ee
😎 Deploy Preview	https://deploy-preview-10145--docusaurus-2.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

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

[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 62	🟢 98	🟢 96	🟢 100	🟠 88	Report
/docs/installation	🟠 65	🟢 96	🟢 100	🟢 100	🟠 88	Report
/docs/category/getting-started	🟠 75	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog	🟠 67	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog/preparing-your-site-for-docusaurus-v3	🟠 58	🟢 96	🟢 100	🟢 100	🟠 88	Report
/blog/tags/release	🟠 69	🟢 100	🟢 100	🟠 80	🟠 88	Report
/blog/tags	🟠 74	🟢 100	🟢 100	🟢 90	🟠 88	Report

[github-actions]

Size Change: 0 B

Total Size: 1.71 MB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/codeTranslations.json	2 B
website/.docusaurus/docusaurus.config.mjs	26.9 kB
website/.docusaurus/globalData.json	107 kB
website/.docusaurus/i18n.json	930 B
website/.docusaurus/registry.js	275 kB
website/.docusaurus/routes.js	179 kB
website/.docusaurus/routesChunkNames.json	119 kB
website/.docusaurus/site-metadata.json	2.17 kB
website/build/assets/css/styles.********.css	112 kB
website/build/assets/js/main.********.js	853 kB
website/build/index.html	38.1 kB

_{compressed-size-action}