Added Liquid Filter methods for UnitsML template

[suleman-uzair]

Metanorma PR checklist

• Breaking changes (list related PRs)
• Documentation update required (create task for this)
• External dependency introduced (documentation update need)
• Gem with native library introduced

This PR updates the Liquid filter methods for UnitsML template processing.

closes #177

[suleman-uzair]

@ronaldtse, Here's the list of draft PRs (ready on my end) for this feature:

• Add UnitsML XML Schema specification generated from XSD unitsml/docs#9
• Updated Xml::Element to support to_liquid method lutaml/lutaml-model#463
• feat: lutaml_xsd command support #246
• Registered LutamlXsdPreprocessor in Asciidoctor::Extensions metanorma-standoc#1086
• feat: add XSD parsing support lutaml/lutaml#157
• fix: except option support lutaml/lutaml-model#471

I have included the HTML file here for you to review the presentation of the output, generated with the following command:

bundle exec metanorma sources/unitsml_xsd_docs/document.adoc -t cc

This implementation doesn't contain any diagrams/images yet, based on our previous discussion:

let's get the document first without the diagrams, we should not do all at once

Please let me know if you have any comments or require any changes.

cc: @HassanAkbar

[Copilot]

Pull request overview

This PR adds Liquid filter methods and template processing capabilities for UnitsML XSD schema documentation generation. The changes introduce a new to_xml_representation filter to replace the previous used_by filter, add support for direct block processing of XSD schemas with Liquid templates, and refactor test fixtures to use external files instead of inline strings.

Key changes:

• Introduced new Liquid filter to_xml_representation for XML schema rendering
• Added direct block syntax for XSD processing: lutaml_xsd::<schema>[<context>,<template>,options]
• Refactored tests to use external fixture files for maintainability
• Updated metadata structure with semantic-metadata section

Reviewed changes

Copilot reviewed 22 out of 23 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
spec/spec_helper.rb	Added strip_filename helper, updated BLANK_HDR with semantic-metadata section and changed title attribute from format to type
spec/metanorma/plugin/lutaml/lutaml_xsd_preprocessor_spec.rb	Refactored tests to use external fixture files, added new test context for template-based XSD documentation
spec/metanorma/plugin/lutaml/*_spec.rb	Updated tests to use strip_filename helper for image filename attributes
spec/fixtures/lutaml/unitsml_liquid_templates/*.adoc	Added Liquid template files for rendering XSD elements, complex types, and attribute groups
spec/fixtures/lutaml/*.xml	Added expected output fixture files for UnitsML schema documentation tests
spec/fixtures/lutaml/xsd_schemas/omml.xsd	Added documentation annotation to CT_OMathArgPr complex type
lib/metanorma/plugin/lutaml/utils.rb	Added LIQUID_INCLUDE_PATH constant for default template location
lib/metanorma/plugin/lutaml/lutaml_xsd_preprocessor.rb	Added direct block processing support, template file reading, and options parsing
lib/metanorma/plugin/lutaml/lutaml_preprocessor.rb	Added assign_options_in_liquid method stub
lib/metanorma/plugin/lutaml/lutaml_ea_xmi_base.rb	Moved LIQUID_INCLUDE_PATH to Utils module
lib/metanorma/plugin/lutaml/liquid/custom_filters/xsd/used_by.rb	Removed (94 lines deleted)
lib/metanorma/plugin/lutaml/liquid/custom_filters/xsd/to_xml_representation.rb	Added new filter for XML representation rendering
lib/metanorma/plugin/lutaml/base_preprocessor.rb	Extracted file_system method, added FILE_SYSTEM_PATTERNS constant
Gemfile	Updated dependencies including metanorma-standoc branch reference

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[opoudjis]

@suleman-uzair @HassanAkbar @ronaldtse What is the status of this PR?