docs: Major revisions above the fold

Start making the initial list more feature-rich and appealing. A long way to go yet, but I need to stop SOMEwhere so Tomas can review this work.

Observations

• Several of the first items under ## Features were short enough that they could be blended into the unordered list at the top of the page.
• We could probably carve off the snippet-related features into a separate page.
• Fixed some minor markdown issues:
  • list indentation
  • bolding used instead of a subheading

Related issues

• Related to create-stage#12955 (closed) and specifically create-stage#12955 (comment 740124274) where I noted work needed doing.