Adds a new field to groups, Closely Linked Artists, which shows at the top of the group's info page:

A backlink to the group also shows on the corresponding artist pages:

Closely Linked Artists is an annotated reference list—a new basic data structure. The "alias" annotation gets a custom presentation, following along #550 and #568.

The implementation for annotated reference lists mostly stems from annotated artwork reference lists (no PR), which are now coded in terms annotated reference lists. This PR however introduces reverse annotated reference lists. It also factors out some code common in forward reference lists, and introduces related handy data utilities.

• inputNotFoundMode: Now a utility function (ala inputWikiData), instead of hard-coded for each use.
• raiseResolvedReferenceList: Now a composition of its own, factoring out behavior related to applying a specified notFoundMode. This is sufficiently generic for use in all forward reference lists (and similar data). It's also a bit nicer of an implementation compared to the existing code in withResolvedReferenceList.
  • Rather than check non-nullness of results itself, this takes a filter input, which (of course) may be computed separately from the results input where relevant.
• performAvailabilityCheck: Now a standalone utility function. Only accessible as a helper in #composite/control-flow.
• withAvailabilityFilter: New control-flow compositional step. This is just like withResultOfAvailabilityCheck (which underlies many control flow steps), but operates on a data list. It's typically more useful as a compositional step, combining nicely with withFilteredList and anything that takes a filter as an input—including raiseResolvedReferenceList.
• referenceListInputDescriptions and referenceListUpdateDescription: Now utility functions, bundled together in a reference-list-helpers.js helper. These are closely related and responsible together for conveniently building the custom update descriptions that reference lists use.
  • These newly include support for providing multiple classes or reference types (as in mixed reference lists), and reflecting those in the update description.
  • These are relevant to reference list property compositions (#composite/wiki-properties), not withResolved... compositions (#composite/wiki-data).
• annotatedReferenceList and withResolvedAnnotatedReferenceList: Like normal reference lists, but with an annotation property for each item. At the moment the reference itself is always specified in a reference property, and exposed (transformed) in thing.
  • Implementation derives from referencedArtworkList, which is now in terms of this, and still includes the relevant find.mixed / combineWikiDataArrays stuff.
• reverseAnnotatedReferenceList and withReverseAnnotatedReferenceList: The usual. Spiritually these are similar to reverse contribution lists, because they're reversing based on a property, but they are also responsible for flipping the directionality of the reference: thing points forward in a forward list, backward in a reverse list.
  • We might change this to align with contribution lists, where every in-between node points in both directions and is identity/value-equal whether you found it forwards or backwards. For now we're letting these differently shaped data structures coexist, though.
• withStretchedList: New generic data composition that underlies the flipping behavior in reverse annotated reference lists. It repeats each item in a list by a corresponding length.