Change feature_id to feature-id in changelogs

[lcawl]

Background

While working on #2412, I encountered this error on the `docs-builder changelog bundle" command:

../docs-builder/.artifacts/publish/docs-builder/release/docs-builder changelog bundle --all --directory ./docs/changelog/
...
Error: Failed to parse YAML: Property 'feature-id' not found on type 'Elastic.Documentation.Services.Changelog.ChangelogData'.

The command worked when I updated the changelog files to use feature_id: xxx but that does not align with the schema in https://docs-v3-preview.elastic.dev/elastic/docs-builder/tree/main/contribute/changelog and AFAICT there was no conscious choice to use underscore and IMO it's less confusing to keep the command option and the schema in sync.

Summary

Updated the docs-builder changelog add command and related code to use feature-id instead of feature_id.

Changes Made:

• ChangelogData.cs: Added [YamlMember(Alias = "feature-id", ApplyNamingConventions = false)] to the FeatureId property to ensure YAML serialization uses feature-id instead of feature_id.
• ChangelogServiceTests.cs: Updated the test assertion to check for feature-id instead of feature_id.
• Documentation: Already uses feature-id correctly:
  • Command help shows --feature-id
  • Schema documentation shows feature-id:
  • Generated YAML comments show # feature-id:

The C# parameter name featureId remains camelCase (standard), and ConsoleAppFramework converts it to --feature-id for the CLI. The YAML output now uses feature-id with a hyphen as required.

Tests

• All 15 changelog tests pass
• Build succeeds with no errors

Alternatives

If it's preferrable to stick with feature_id in the changelog files, IMO we should change the command option to --feature or --feature_id to avoid confusion.

Generative AI disclosure

1. Did you use a generative AI (GenAI) tool to assist in creating this contribution?

• Yes
• No

2. If you answered "Yes" to the previous question, please specify the tool(s) and model(s) used (e.g., Google Gemini, OpenAI ChatGPT-4, etc.).

Tool(s) and model(s) used: composer-1 agent