fix(core): Property's type should be nullable

[nandorholozsnyak]

Pull Request: Support Optional type Field in Spring Boot Metadata & Template Cleanup

Summary

This PR implements support for configuration properties without a type field, as allowed by the Spring Boot metadata specification. It also refines Handlebars templates to prevent extra blank lines in generated documentation.

Changes

• Core Logic

  • The type field is now optional in property metadata parsing and grouping.
  • Model and grouping logic updated to handle missing type values gracefully.

• Templates

  • Handlebars templates (.hbs files) for Markdown, HTML, and AsciiDoc now use the tilde (~) in if statements to suppress unwanted whitespace.
  • All conditional rendering for the type field is now whitespace-safe.

• Tests

  • Added and updated tests to cover properties without a type.
  • Adjusted test resources and assertions for the new logic.
  • All unit and integration tests pass.

Motivation

Spring Boot does not require the type field for configuration properties. This change ensures compatibility and prevents errors for such cases. Template improvements result in cleaner, more predictable documentation output.

Notes

• No breaking changes for users who provide the type field.
• All tests pass and the build