Fix YAML functions documentation and increase test coverage

[aknysh]

what

• Fixed incorrect .outputs. prefix in !terraform.state documentation examples
• Fixed confusing component/output name collision in !terraform.output documentation
• Fixed incorrect syntax in website/docs/functions/index.mdx (vpc.vpc_id → vpc vpc_id)
• Fixed broken link generation in doc-release-data plugin for index.mdx files with id: index
• Added comprehensive test coverage for YAML functions:
  • YQ expression patterns (bracket notation, defaults, pipes)
  • !env function unit tests
  • !include integration tests
• Added test fixtures for bracket notation with special characters (slashes, hyphens)

why

• Users reported confusion with documentation examples that showed incorrect YQ expression syntax
• A user reported issues with bracket notation containing forward slashes in map keys - investigation confirmed the syntax is correct but documentation needed clarification
• The doc-release-data plugin incorrectly generated /index paths for files like functions/index.mdx with id: index, causing broken links on the /unreleased page
• Test coverage for YAML functions was insufficient for edge cases like bracket notation with special characters

references

• YQ Guide
• YQ Recipes
• Internal tracking document: docs/fixes/yaml-functions-yq-expressions.md

[mergify]

Warning

This PR exceeds the recommended limit of 1,000 lines.

Large PRs are difficult to review and may be rejected due to their size.

Please verify that this PR does not address multiple issues.
Consider refactoring it into smaller, more focused PRs to facilitate a smoother review process.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues found.

Scanned Files

None

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 75.45%. Comparing base (c90352d) to head (3f7c882).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2028      +/-   ##
==========================================
+ Coverage   75.43%   75.45%   +0.02%     
==========================================
  Files         793      793              
  Lines       73666    73666              
==========================================
+ Hits        55571    55586      +15     
+ Misses      14583    14572      -11     
+ Partials     3512     3508       -4     

Flag	Coverage Δ
unittests	75.45% <ø> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.
see 9 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

These changes were released in v1.205.0.