Convert YAML file paths to abspath

[ewu63]

Purpose

In order to support out-of-source builds (say via VS code extensions), I have converged the input filepath for the YAML options to use abspath, by fetching the source RST file that called the extension via self.state.document.attributes["source"]. This does mean however that the specified file path should be relative to the RST file itself, rather than the root doc directory where conf.py is stored (i.e. the directory you call sphinx from). The only package where this affects things should be pyOptSparse, and I will push a fix for that soon.

Expected time until merged

ASAP

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Tested on ADflow and pyOptSparse.

Checklist

• I have run flake8 and black to make sure the code adheres to PEP-8 and is consistently formatted
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation