Make code blocks scrollable horizontally

[ebkalderon]

It seems that code blocks currently default to word-wrapping the text horizontally instead of allowing the reader to scroll left and right. This means that code samples published with this theme that drift rightward end up being wrapped, breaking their formatting and readability. This could be fixed by adjusting overflow, I think?

[ejmg]

does #12 do the job well enough? i added a long code segment that demonstrates the styling update here

[ejmg]

i restricted overflow to the x axis because otherwise i would have to make a decision over what constitutes an adequately long code block along the y axis and i punted on that issue. i could be arbitrary and put a line in the sand now but i didn't care to.

[ebkalderon]

Would overflow-x: auto; not be sufficient here? Why or why not? I'll give the PR with overflow-x: scroll; a try regardless, though. Thanks for opening it.

[damccull]

I personally like this solution. I prefer the Y-axis show the full length code instead of trying to scroll.