Relative path for SSH `Include` is resolved relative to $PWD instead of SSH config file

[injust]

In my SSH config file at ~/.ssh/config, I have Include test. I put some of my config in ~/.ssh/test.

When $PWD is ~/.ssh, et reads my full SSH config. When I am in any other directory, et does not use my full config and can't resolve the hostname.

This was previously reported in #197 and #371, but never actually fixed. Absolute paths work (including paths with ~), but not relative paths.

---

et 6.2.11