Improve documentation & reference matter & motivating examples & how-to sections

0. The current motivating example `rremark` is not really a hot-sell 😞 There are much better motivating examples elsewhere in the article, mention those first ---e.g., by having a whirlwind of features/special-blocks/links presented first, then talking about the machinery required to make them happen.

1. Top-level sections that are relatively short, such as sec 2, sec 3, & sec 8 can be converted into "(advanced) exercises" of section 1.5, or otherwise can be mentioned along the way in section 1? Something to consider.

2. There is a difference between "tutorial" and "reference" and "theory". It seems that the webpage is trying to do "theory" in section 1, then "tutorial" in section 1.5, then "how-to-guide/recipes" in sections 2-13, and the "reference" is happening in the github readme. None of these is done specifically well.
- Please make the intent of each of these super clear & explicit, then actually follow through.
- E.g., the github readme should have just a reference of the links/blocks defined, their args, and a link to the webpage for more info. Aside: The readme looks like trash `‿︵(ಥ﹏ಥ)‿︵`