Handle doc locations when file is in parent directory

[Blacksmoke16]

Fixes #15888

[Blacksmoke16]

Okay, am I missing something as to why these tests are failing on windows? Should to_native not normalize the path I provide to whatever the underlying OS expects?

[straight-shoota]

Path.[] already constructs a native path. The call to to_native is always a no-op.

But you're explicitly constructing a path with forward slash as separator (Path["src/foo.cr"]). This is entirely valid in Windows, despite backslash being the more idiomatic variant. to_windows conversion does not change forward slash directory separators to backslash.
If you want canonical paths per platform, you should construct the path from individual components: Path["src", "foo.cr"].

EDIT: Or call Path#normalize. This transforms all forward slashs into backslashs on a Windows path.