Update 7-15-2025

[linearcombination]

• Fix issue with ordering of books in document title and document content for book then lang assembly strategy, i.e., interleave by chapter.
• Prior to this PR, visual section separators (horizontal line) were always added, but there were some glitches where the horizontal line would only show for one half the width of the page at the end of two colum layout sections. I decided it would be better to make adding visual section separators a user choice on the final submission page, i.e., the settings page, of the document generation process (located under "Optional Settings") while also eliminating this glitch. This led to the the next item which was the way to handle docx document generation in a nicer way:
• Restructure docx assembly so that document parts are accumulated but not actually created until the end when the parts are finally composed in a centralized location. This helps code deduplication and follows a lazy instantiation pattern that is easier to reason about and less imperative.
• Add tests for content ordering by bible book order.
• Some additional code deduplication for document_generator.generate_document and document_generator.generate_docx_document by sharing common code through a refactor.