Terminal suggest: Add / or \ to the end of directories as appropriate

[Tyriar]

I fine tuned the pwsh completions to handle this really nicely. The rules are:

• Add a slash to every folder that's provided
• Don't add slash to the end of simple . and .. completions. This is done since they're special and are often used on their own, so users are required to add the slash to continue on. This is somewhat of a remnant of runOnEnter being the default but I think it makes sense to keep it this way.
• Add a slash to the end of compound .. completions (eg. ../ should have the completion ../../)

This allows navigating directories intuitively with arrows + tab