A one-line whitespace fix on the gtag script tag

Shortest PR I'll ever merge on this blog: +1 / −2. A single whitespace tweak in pages/_document.js that collapses a two-line JSX attribute onto one line.

// before
<script
  async
  src={`https://www.googletagmanager.com/gtag/js?id=${…}`}
/>
 
// after
<script
  async src={`https://www.googletagmanager.com/gtag/js?id=${…}`}
/>

Semantically identical. Runtime identical. Functionally a no-op. I shipped it as a PR anyway because:

1. It was sitting as a dirty file in my working tree after PR #1 merged.
2. Merging dirty branches later creates noise in blame that's harder to untangle than "one PR per visible change."
3. PRs are free. GitHub doesn't charge by the diff line.

There is no deep lesson here. This post exists because the PR exists, and I'm backfilling a post for every PR on this blog for completeness.

PR: https://github.com/StevieIsmagic/vercel_blog/pull/2