Fix mods not loaded on Linux/macOS if their path has trailing whitespace

[jakerosado]

Resolves #905

[Pathoschild]

Thanks for the PR!

Unfortunately I see a few issues with this approach:

• This also allows leading whitespace, which won't work on any OS so far as I know.
• Path normalization is often used for user input (e.g. from content packs) and before path concatenation, where surrounding whitespace is virtually never intended and can cause errors.
• This would let mod authors on Linux/macOS accidentally create a mod which can't work on Windows.

I think it'd be better to go in the other direction. To help mods work consistently on all platforms, SMAPI could explicitly validate that there are no mod folder paths with trailing whitespace and show a friendly error message explaining how to fix it.

[jakerosado]

To my surprise, I found leading and trailing whitespaces allowed on my Linux partition. It's not something I ever considered trying prior to seeing this issue.

Ultimately, I think you're right. While I'm sure there's some underlying reason for wanting these kinds of whitespaces on *nix systems in certain circumstances, I don't see any direct relevance for wanting to encourage it in SMAPI. I'll revert the commit and come up with an error message instead.

[Pathoschild]

I'll close this, but feel free to submit a new PR for the suggested change!