RdfIri.withFragment constructor

Creates an IRI mapping by appending a fragment to a base IRI.

This constructor is specifically designed for classes that represent IRI terms which differ from a base IRI only by their fragment identifier. It works with any URI scheme (hierarchical like https:// or non-hierarchical like tag:), making it ideal for identifier classes that represent fragment-based references within a document.

The generator will:

1. Process baseIriTemplate to get the base IRI
2. Strip any existing fragment from the base IRI (everything after and including #)
3. Process fragmentTemplate to get the fragment value
4. Append #${fragmentValue} to create the final IRI

Both templates support the standard placeholder system:

• Property placeholders from @RdfIriPart annotated properties
• Context variables from global providers, @RdfProvides, or parent's providedAs
• Reserved expansion with {+variable} to preserve URI structure

Example usage:

@RdfIri.withFragment('{+documentIri}', 'section-{sectionId}')
class SectionReference {
  @RdfIriPart()
  final String sectionId;

  SectionReference(this.sectionId);
}

@RdfGlobalResource(
  DocumentClass.classIri,
  IriStrategy('tag:example.org,2025:document-{id}', 'documentIri')
)
class Document {
  @RdfIriPart()
  final String id;

  @RdfProperty(Vocab.currentSection)
  final SectionReference section;
  // Section IRI will be: tag:example.org,2025:document-123#section-intro
}