fix: Use POSIX paths when inserting import statements correctly this …

[nmn]

Fixes #774

I was finally able to test this fix on a Windows machine and this finally works as expected.

[github-actions]

workflow: benchmarks/size

Comparison of minified (terser) and compressed (brotli) size results, measured in bytes. Smaller is better.

@stylexjs/[email protected] size:compare
./size-compare.js /tmp/tmp.I5hhWV9PbE /tmp/tmp.y5g6aDRi0l

Results	Base	Patch	Ratio
stylex/lib/stylex.js
· compressed	729	729	1.00
· minified	2,541	2,541	1.00
stylex/lib/StyleXSheet.js
· compressed	1,266	1,266	1.00
· minified	3,776	3,776	1.00
rollup-example/.build/bundle.js
· compressed	562,983	562,983	1.00
· minified	10,185,368	10,185,368	1.00
rollup-example/.build/stylex.css
· compressed	99,229	99,229	1.00
· minified	745,845	745,845	1.00

[BjornHMS]

Hey @nmn thanks for all your work on this.
This doesn't seem to work either, I now get:

import "../C:/projects/website/src/stylex_bundle.css";

As you can see it's not actually making a relative path.
I think path.posix.relative expects the format to not be in a windows absolute path format.

However path.relative was returning a relative path, but the slashes were wrong... so I changed path.posix.relative back to path.relative and used the new toPosixPath function .. and now it works!

Edit: to clarify .. The only changes needed for this branch to work for me was to change path.posix.relative to path.relative.

[nmn]

@BjornHMS Yes, you're right! That was the code I tested on my Windows test machine, but there was an oversight when I rebased my PR. I'll fix it.

[nmn]

Created #801