`URIs.append` eats trailing slashes when not at the path root

[dmolesUC]

Steps to reproduce:

puts BerkeleyLibrary::Util::URIs.append('https://example.test/', '?', 'foo=bar')
puts BerkeleyLibrary::Util::URIs.append('https://example.test/path/', '?', 'foo=bar')

Expected:

Both output URLs have a / before the ?, as:

https://example.test/?foo=bar
https://example.test/path/?foo=bar

Actual:

Second output URL is missing the /, as:

https://example.test/?foo=bar
https://example.test/path?foo=bar

Notes

This Golang issue comment notes that Go's path.Clean has this behavior of stripping the trailing slash (and that such behavior isn't desirable for URL paths); I wouldn't be surprised if we have the same behavior in our Paths.join and/or Paths.ensure_abs (as used in URIs::Appender.to_uri), since Paths was patterned after the Go package.