Correctly specify the source path to a logo to copy_asset_file

[Cadair]

I think this fixes #1385, I think that bug report is expecting to be able to pass a logo in the docs/_static directory but according to the docs here: https://pydata-sphinx-theme.readthedocs.io/en/stable/user_guide/branding.html#different-logos-for-light-and-dark-mode the path should be relative to conf.py.

I think the actual bug is that we were not passing the correct source to the sphinx copy function which exits silently (for some reason) if the source does not exist.

[drammock]

this looks correct to me, but hopefully @12rambau has time to look too, as I think he wrote much of the logic for handling light/dark logos. If not, I'll merge later this week.

[drammock]

on second look, I'm not sure this is correct. If the logo path is supposed to be relative to conf.py then shouldn't this be:

Suggested change

	copy_asset_file(str(Path(app.srcdir) / path_image), staticdir)
	copy_asset_file(str(Path(app.confdir) / path_image), staticdir)

(docs: https://www.sphinx-doc.org/en/master/extdev/appapi.html#sphinx-runtime-information)

[Carreau]

I believe the reason is that it's already referencing (Path(app.srcdir) / path_image) on line 73:

        if not (Path(app.srcdir) / path_image).exists():

We likely want to use a variable and reuse it to make sure there is no inconsistencies.

[Carreau]

and copy_asset_file(path_image, staticdir) was wrong as afaict, this was referencing path relative to CWD, and just silently do nothing if the source does not exist.

[Carreau]

I've pushed an extra commit. As the code on line 73 was checking existence with respect srcdir, I think this is self-coherent, I think that wether we need to use srcdir, or confdir is a separate conversation.

[Carreau]

srcdir, or confdir

(we can potentially loop on both/warn/deprecate the wrong one).

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
src/pydata_sphinx_theme
logo.py
translator.py
Project Total

This report was generated by python-coverage-comment-action

[Carreau]

Ok, let's get that in, if we want to change from srcdir ton confdir we'll do that later.