Use ~/.local/bin/poetry if it exists

[colindean]

As a better default or another step in resolution, let's check for ~/.local/bin/poetry and use it if it exists and ~/.local/bin isn't in the PATH, and of course, tell the user about the misconfiguration.

[colindean]

This comes off of #42: do the thing that works in most cases and tell the user that we're, uh, autocorrecting them.