Improve the "Recently Updated" list to include the most recent (only one Git commit) posts.
This change has two benefits:
1. The post update list is consistent with the git commit timeline.
2. Avoid users not having a list of updates to show when they first publish a site.
- update class name of the spacing, font style, cards and toasts
- update attribute names & tooltip usage
- remove custom smooth scroll
- syntax colors
There is the current ability to set `last_modified_at` in the front matter of post and use that datetime instead of the built in logic.
New feature in post.html: if the modified date time matches the date of the post, then don't show "Updated xxxx"
