Parameterized sidebars in frontmatter (e.g. APIRef, DefaultAPISidebar)

[caugner]

Most sidebar macros do not have a parameter, so they can be specified directly in frontmatter like this:

sidebar: xmlsidebar

Other sidebar macros have a parameter like this:

{{APIRef("Ink API")}}

In particular, this means that the sidebar macros have to be replicated in translated content, whereas the sidebar frontmatter is inherited (explaining few matches for sidebar: in translated-content).

Possible solutions:

1. Extend the type of the sidebar frontmatter, e.g. string | Record<string, string>:

   sidebar:
     apiref: Ink API
   

2. Add a separate API field:

   api: Ink API
   sidebar: apiref
   

3. Derive the API from the slug following the API reorg