Update: Improve manual install guide of @astrojs/tailwind integration

[dreyfus92]

What kind of changes does this PR include?

• New or updated content

Description

• What does this PR change? Give us a brief description.
  Improved guide for manual install of TailwindCSS with Astro.

Related Issue / Implementation PR

• Closes Issue # Manual install guide of Tailwind doesn't explain how to set up Tailwind's config for Astro #4587

[netlify]

✅ Deploy Preview for astro-docs-2 ready!

Built without sensitive environment variables

Name	Link
🔨 Latest commit	75b876a
🔍 Latest deploy log	https://app.netlify.com/sites/astro-docs-2/deploys/650bcadeda89d90008e991fa
😎 Deploy Preview	https://deploy-preview-4770--astro-docs-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.

[sarah11918]

hey @dreyfus92 ! We realized this after your nodejs PR too, but I totally should have reminded you to PR this in the Astro repo, not docs directly! These are automatically pulled in from the integration package readmes there, and only the translations are actually done in this repo directly!

If you look at the raw top of the file of the English version of these, or click on "Edit this page" from the docs site, it should take you to the direct file you need to go to. Would you mind updating these over there?