Bug in ChunkIncr

[dinocore1]

https://github.com/jmesmon/hash-roll/blob/a964a874bed4398a02d6c8136cd7d0bdd8064f36/src/gear.rs#L114

I think this should be return Some(i+1)

[codyps]

This does look like a potential bug. It looks like some tests validating ChunkIncr and Chunk behave the same could be helpful in detecting this type of error.