## Summary
**Improve title detection in pptx documents** The default title
textboxes on a pptx slide are now categorized as titles.
**Improve hierarchy detection in pptx documents** List items, and other
slide text are properly nested under the slide title. This will enable
better chunking of pptx documents.
Hierarchy detection is improved by determining category depth via the
following:
- Check if the paragraph item has a level parameter via the python pptx
paragraph. If so, use the paragraph level as the category_depth level.
- If the shape being checked is a title shape and the item is not a
bullet or email, the element will be set as a Title with a depth
corresponding to the enumerated paragraph increment (e.g. 1st line of
title shape is depth 0, second is depth 1 etc.).
- If the shape is not a title shape but the paragraph is a title, the
increment will match the level + 1, so that all paragraph titles are at
least 1 to set them below the slide title element
This refactor solves a problem or two, the big one being recursing into
group-shapes to get all shapes on the slide, but mostly lays the
groundwork to allow us to refine further aspects such as list-item
detection, off-slide shape detection, and image-capture going forward.
Reviewers: I recommend reviewing commit-by-commit or just looking at the
final version of `partition/docx.py` as View File.
This refactor solves a few problems but mostly lays the groundwork to
allow us to refine further aspects such as page-break detection,
list-item detection, and moving python-docx internals upstream to that
library so our work doesn't depend on that domain-knowledge.
