Update contributions to reference pre-commit hooks

[quixoticmonk]

Static analysis would compare the documentation generated versus what is committed.
Reference : https://github.com/aws-ia/terraform-aws-bedrock/blob/main/.project_automation/static_tests/static_tests.sh#L71

[scottschreckengaust]

The README.md is generated from source files, and so the markdown is linting those source files directly. The pre-commit ensures the README.md has no direct edits (outside the source files).

Here are a few more details within the contributing guide.