"Header only" option

[hoffm386]

For the DS curriculum, we often avoid adding the actual README as HTML in Canvas

Instead, we just add the <header> part and leave the rest of the assignment description blank, then also set up a link to our cloud IDE (IllumiDesk) by setting the submission type to "External Tool"

My proposal is to add a flag --header-only (although the actual flag name is flexible) that creates a page with the appropriate title and <header> and leaves off everything else

Creating just the header is really just string interpolation so I wasn't sure how best to incorporate this into the overall gem flow. In my fork I have a "hack" version that still creates the entire README as HTML, then throws that away to just include the header. That doesn't seem ideal for overhauling an entire course, but more structural reorganization seemed more likely to break something

[hoffm386]

Clarifying further, this thing I call the "header" (based on the HTML element used) is also called the --fis-links or -l option in the current documentation