website improvements

[nedtwigg]

• make the order jvm, py, js, ... (since jvm and py both actually work)
• fix(deps): update dependency shiki to v1 - autoclosed #202
• Update dependency eslint to v9 #395
• bring back language-specific dropdowns per-header
  • this is a screenshot before Remove cool multilanguage heading dropdown, many small styling improvements #93
  • 
  • compared to now we have
  • 
  • (plus) popout
  • (plus) anchor link
  • (minus) language dropdown

I think both the anchor link and the popout are really nice to have if we can have both. In problem terms:

• we want the user to know that Selfie is available for many languages
• we want the user to have concrete examples in every supported language, and feel easy to switch between them
• we want the user to be able to drill down deeper into the subject they're looking at

I lean towards: `title, anchor. . <pop-out icon, no background>

[nedtwigg]

Huzzah!