Confusing error message when linting outside of the WPT directory

[domenic]

#9879 helped me run the WPT lint on jsdom tests, thanks!

However, I get error message, which does not have any impact on the exit code of lint.py (and so I can ignore it), but is confusing:

fatal: ..\to-upstream\lint.ignore: '..\to-upstream\lint.ignore' is outside repository at 'C:/Users/d/OneDrive - domenic.me/Code/GitHub/jsdom/jsdom/test/web-platform-tests/tests'

Setup:

outer/wpt             (<-- full WPT checkout)
outer/to-upstream

CD to outer/wpt

Run:

python ./wpt.py lint --repo-root ../to-upstream --all

This successfully lints the tests in outer/to-upstream, and even applies the ignore file at outer/to-upstream/lint.ignore.

But it gives the above confusing message.