Breadcrumb and title are sticked together in docs

[phamduylong]

Probably not intentional but the h1 here and breadcrumb content is sticked together (see cursor highlighted text). Can add a colon or something.

Browsed through the code and it happens here. I can throw a PR quite quickly if the proposed solution is approved (separating them with a colon).

[Conduitry]

This was a styling issue caused by a bug in Svelte 5.1.10 with :not() selector handling. We've reverted to 5.1.9 for now (#810).