Move the demo recording to the quick start section

Author: devjgm

README.md

@@ -12,8 +12,6 @@ ________________
 Terminal slide presentations from a single markdown file. Like Keynote,
 but it's not, and it lives in your terminal, like you.
 
-![keynot demo](https://raw.githubusercontent.com/devjgm/keynot/main/assets/demo.gif)
-
 - One `.keynot` file per presentation: YAML frontmatter for metadata and
   theming, slides in plain markdown separated by `---`, HTML comments as
   speaker notes (a format in the spirit of [marp](https://marp.app))
@@ -40,6 +38,8 @@ keynot play talk.keynot    # present it
 keynot check talk.keynot   # validate and summarize a file
 ```
 
+![keynot demo](https://raw.githubusercontent.com/devjgm/keynot/main/assets/demo.gif)
+
 Useful `play` flags:
 
 ```sh