Update contribute section under community

Update the contribute section to:
- Update the number of contributors (and organizations) for each GitHub repo
- Missing repos: delta-examples, delta-docs (??)

Start at the Community section's contribute content and inspect how each GitHub repository's contributor and organization counts are represented. Confirm the current repositories, investigate whether delta-examples and delta-docs belong there, and consider the work done when all listed repositories have accurate counts and the missing-repository question is resolved.

Written by the indexing model from the issue text.