clarify the documentation, add a few tests. Fixes pr 12032 Fixes pr 12034 (cherry picked from commit ebe9453e73)
ebe9453e73
setup/path-to-relative' that supersedes
`setup/private/path-utils'. The API is a little different: instead of getting the alist and the path, there's a curried function that gets the alist and produces a function to do the substitutions.