Fix broken documentation for output method target parameter

[Copilot]

Problem

The documentation for the output method's target parameter was displaying with broken formatting on the generated documentation site. The parameter description was split across multiple lines with malformed text:

target: specify target file type ("vcd", "svcd", "dvd", "dv" or "dv50\
        "with optional prefixes "pal-", "ntsc-" or "film-")

This made the documentation difficult to read and appeared as damaged text in both the Python docstrings and the rendered HTML documentation at https://livingbio.github.io/typed-ffmpeg/reference/ffmpeg/#ffmpeg.VideoStream.output.

Root Cause

The issue originated from the source data file (src/ffmpeg/common/cache/list/options.json) which contained a literal \n (backslash-n) character embedded in the help text. This represented a C-style string continuation from the original FFmpeg source code that was not being properly handled during code generation.

Solution

This PR implements a comprehensive fix with two components:

1. Immediate Fix

• Corrected the malformed documentation in the generated file src/ffmpeg/dag/io/output_args.py
• The target parameter description now appears on a single line as intended

2. Future-Proof Fix

Added a normalize_help_text Jinja2 filter to the code generation system (src/scripts/code_gen/gen.py) that:

• Replaces literal \n sequences followed by whitespace and quotes with single spaces
• Collapses multiple consecutive whitespace characters into single spaces
• Ensures all help text is properly formatted on a single line

Updated the code generation templates (src/scripts/code_gen/templates/dag/io/_output.py.jinja and output_args.py.jinja) to apply this filter to all help text during generation.

Result

The documentation now correctly displays as:

target: specify target file type ("vcd", "svcd", "dvd", "dv" or "dv50" with optional prefixes "pal-", "ntsc-" or "film-")

Testing

• ✅ Verified Python docstrings display correctly
• ✅ Built documentation with mkdocs build --strict successfully
• ✅ Confirmed HTML output shows proper single-line formatting
• ✅ All linter checks (ruff) pass
• ✅ Module imports and functionality work as expected

This fix ensures that both the current documentation and any future code generation will properly handle help text containing line breaks or C-style string continuations.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Documentation for "output" method is damaged</issue_title>
<issue_description>Documentation for output method is damaged.

See here:

https://livingbio.github.io/typed-ffmpeg/reference/ffmpeg/#ffmpeg.VideoStream.output

...and scroll down below the "Parameters" table.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #769

---

💬 Share your feedback on Copilot coding agent for the chance to win a $200 gift card! Click here to start the survey.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.24%. Comparing base (c1b4ba9) to head (e4e4d01).
⚠️ Report is 3 commits behind head on main.

❌ Your project status has failed because the head coverage (78.74%) is below the target coverage (80.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #770      +/-   ##
==========================================
+ Coverage   78.74%   81.24%   +2.49%     
==========================================
  Files          51       78      +27     
  Lines        3331     4553    +1222     
==========================================
+ Hits         2623     3699    +1076     
- Misses        708      854     +146     

Flag	Coverage Δ
3.10	78.74% <ø> (ø)
3.11	78.71% <ø> (ø)
3.12	78.71% <ø> (ø)
backend	78.74% <ø> (ø)
python	78.74% <ø> (ø)
python-3.10	88.05% <100.00%> (?)
scripts	88.05% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/ffmpeg/dag/io/output_args.py	100.00% <ø> (ø)
src/scripts/code_gen/gen.py	92.70% <100.00%> (ø)

... and 26 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.