Fix site variable replacement error

[atsansone]

This was found when working on #5826

This PR seems to generate errors no matter how I approach remediating the problem.

In _includes/install/macos.md, line 82:

If I write it as:

[tap]: {{site.repo.dart.org}}/homebrew-dart

I get a bad link error.

https://github.com/dart-lang/site-www/actions/runs/9103552699/job/25025626288?pr=5826

Run dart run dart_site check-links
Starting the Firebase hosting emulator asynchronously...
Crawling...

http://localhost:5500/get-dart
- (1580:11) 'official..' => http://localhost:5500/homebrew-dart (HTTP 404)


Stats:
  166163 links
     755 destination URLs
     791 URLs ignored
       0 warnings
       1 errors

Shutting down Firebase hosting emulator...
Done!

Error: Process completed with exit code 2.

If I replace the copy as:

[tap]: https://github.com/dart-lang/homebrew-dart

I get a replaceable content error.

Run dart run dart_site check-site-variable

📂 [File Path]: ./src/_includes/install/macos.md
├── 🔍 [Variable Key]: site.repo.dart.org
└── 🔍 [Variable Value]: https://github.com/dart-lang
    │   
    ├── 📄 [Replaceable content (total 1)]: https://github.com/dart-lang
    └── 💡 [Suggestion]: Replace all "https://github.com/dart-lang" with "{{site.repo.dart.org}}"
        └── ./src/_includes/install/macos.md:82:8


🌏  Done! 
    Total scanned: 
    ├── All variables: 26 (YAML Key)
    └── All files: 185

    Issues: 
    └── Replaceable contents: 1 (Related files: 1)

Error: Process completed with exit code 2.

This leaves me with no way to merge this PR. Help!

[parlough]

I'm assuming this might be because you are using render. There's currently an issue where includes using render doesn't have access to global data. @atsansone Can you try replacing it to include to see if it works as expected?