Add abbreviation count to HIX feedback

[MizukiTemma]

Short description

This PR adds the number of abbreviations used in the content text to the HIX feedback

Proposed changes

• Use jmespath to access deeply nested dictionary values in one step
• Add abbreviations to textlab_api_feedback_categories

Side effects

• None? 👀

Resolved issues

Fixes: #2778

---

Pull Request Review Guidelines