<Plug>VinegarUp breaks scp directory traversing

[proever]

Once a remote buffer is opened in vim via, for example, vim scp://user@host/path/to/file.txt, pressing - to explore the enclosing directory no longer works.

This is due to the trailing / being stripped from the scp URL, leading to scp://user@host/path/to rather than scp://user@host/path/to/.

Typing :Explore does not cause this issue.

Interestingly, once the directory is successfully loading using :Explore, vinegar functions correctly.

[artem-nefedov]

This is still relevant.
Fix looks very simple: add '/' at the end after expanding '%:h'.
This makes it so netrw correctly opens directory for remote edits.
For local edits, it should make no difference.