Length trimming, alphabetizing and pedantic edits to skill descriptions.
Automatically abort .pot updates if there are unparsed .json files.
Add vehicle_parts.json to lang/extract_json_strings.py.
Further edits to skill descriptions.
Change skills.json indent style to 4-space tabs
Merge PR #2662 - Warn on new json
Merge PR #2663 - Skill.json cleanup