Improve error message when windows long pathing issue happens.

[TimothyJones]

The windows long pathing issue (#100) is a common problem with a very unhelpful error message (which is always the same, and unlikely to occur in other situations).

We could detect this particular error when it happens and automatically recommend a solution (or link to the relevant part of the documentation).

[mefellows]

Closing as we have removed Ruby now from the latest version.

[mefellows]

Hmm, or do we - we still wrap the binaries. Perhaps I'll leave this open for the binstubs, we might have something we can do there.