Allow rust code with hashtags to be tested

[compressed]

I ran into an issue today with skeptic where my README contained "#abc which caused issues with the raw string literal parsing...

Since it's a raw string and doesn't allow any escaping, I thought just adding a few more # should handle most of the use cases.

Also, I ran lib.rs through rustfmt.

[brson]

Thanks! Do you mind adding a comment to hashtag-test.md explaining what it's testing?

[compressed]

Sure. I've added the comment now!

[brson]

Thanks!