Refresh styles of table of contents component

[bartaz]

Done

As part of working on documentation layout we are refreshing the styling of an old table of contents component:

• use muted heading for title style
• use link styles on table of contents items to make them accessible
• add spacing between items similar to side navigation

QA

• Open demo
• Review updated examples:
  • https://vanilla-framework-4885.demos.haus/docs/examples/patterns/table-of-contents-sections
  • https://vanilla-framework-4885.demos.haus/docs/examples/patterns/table-of-contents
• Make sure they work fine

Screenshots

[webteam-app]

Demo starting at https://vanilla-framework-4885.demos.haus

[juanruitina]

Sorry for showing up here unannounced, but have some minor feedback. From #4777: may I ask you to make the "On this page" heading an H2 instead of H4? In most cases it should be that heading level.

I'd also remove the colon from the headings, we don't usually use them.

We still need to make a decision on mobile behaviour, but we can handle that separately. So great to see this component improved :)

[chillkang]

LGTM👍