[codex] Fix PERCENT_40 pattern enum name

[Jaywang1013]

Summary

• Fix the MSO_PATTERN_TYPE.PERCENT_40 enum member name, which was missing the leading P.
• Aligns the code with the generated docs and the surrounding percent pattern names.

Fixes #1127

Validation

• PYTHONPATH=src .venv/bin/python -m pytest tests -q -> 2700 passed
• PYTHONPATH=src .venv/bin/behave --format progress --stop --tags=-wip -> 54 features, 973 scenarios, 2914 steps passed
• .venv/bin/python -m ruff check src/pptx/enum/dml.py -> passed