Checking $PATH should also respect directories

[daphil19]

The $PATH environment variable supports directories; meaning an executable that's a direct (i.e, non-recursive) child of the directory is counted as in the $PATH. The language server should check if an entry is a directory and check it's children.

When coupled with #254, this results in the kotlin compiler & stdlib not being found, resulting in a failed build.

[msoucy]

I think the phrase that will help explain this is "relative path"

[daphil19]

Looking closer into this, I realized I was mistaken. The issue I was having was related to homebrew for linux's kotlin installation.

I'll close this ticket and open a new one describing the homebrew situation