[ios, macos] Update and reformat documentation for runtime styling (#7475)

* [ios, macos] Optimized changelog for runtime styling

Changelog entries related to style JSON now lead off with the analogous portion of the runtime styling API.

* [ios, macos] Autolink cross-class property references in docs

jazzy can autolink `Class.property` references in documentation comments.

* [ios, macos] Removed extra blank lines

* [ios, macos] Corrected typo in MGLMultiPoint docs

* [ios, macos] Rewrote shape and feature docs

Rewrote documentation about MGLShape, its subclasses, and MGLFeature to emphasize runtime styling uses over annotation uses, associate each type with real-world concepts, cross-reference related style layer classes, and cross-reference related or easily confused shape classes. Links to the GeoJSON specification have been updated to RFC 7946.

* [ios, macos] Expanded style layer docs

With this change, documentation about style layer classes is nominally based on the documentation in the style specification. However, all the existing layer types’ documentation has been overridden to explain what the layer looks like, relate the layer to a real-world concept, and cross-reference related geometry classes. This change also corrects the description of MGLBackgroundStyleLayer, which erroneously stated that the identifier must be “background”, whereas that only happens to be true by default for Studio template styles.

* [ios, macos] Wrap style layer docs

* [ios, macos] Removed unused code

* [ios, macos] Corrected symbol references in docs

* [ios, macos] Corrected typo in abstract class exception

1 files changed, 21 insertions, 3 deletions

diff --git a/platform/darwin/src/MGLShapeCollection.h b/platform/darwin/src/MGLShapeCollection.h
index a617223ea7..343c2a4322 100644
--- a/platform/darwin/src/MGLShapeCollection.h
+++ b/platform/darwin/src/MGLShapeCollection.h
@@ -7,12 +7,30 @@
 NS_ASSUME_NONNULL_BEGIN
 
 /**
- The `MGLShapeCollection` class represents a shape consisting of one or more
+ An `MGLShapeCollection` object represents a shape consisting of one or more
  distinct but related shapes that are instances of `MGLShape`. The constituent
  shapes can be a mixture of different kinds of shapes.
  
- @note `MGLShapeCollection` objects cannot be added to a map view using
-    `-[MGLMapView addAnnotations:]` and related methods.
+ `MGLShapeCollection` is most commonly used to add multiple shapes to a single
+ `MGLShapeSource`. Configure the appearance of an `MGLShapeSource`’s or
+ `MGLVectorSource`’s shape collection collectively using an
+ `MGLSymbolStyleLayer` object, or use multiple instances of
+ `MGLCircleStyleLayer`, `MGLFillStyleLayer`, and `MGLLineStyleLayer` to
+ configure the appearance of each kind of shape inside the collection.
+ 
+ You cannot add an `MGLShapeCollection` object directly to a map view as an
+ annotation. However, you can create individual `MGLPointAnnotation`,
+ `MGLPolyline`, and `MGLPolygon` objects from the `shapes` array and add those
+ annotation objects to the map view using the `-[MGLMapView addAnnotations:]`
+ method.
+ 
+ To represent a collection of point, polyline, or polygon shapes, it may be more
+ convenient to use an `MGLPointCollection`, `MGLMultiPolyline`, or
+ `MGLMultiPolygon` object, respectively.
+ 
+ A multipolyline is known as a
+ <a href="https://tools.ietf.org/html/rfc7946#section-3.1.8">GeometryCollection</a>
+ geometry in GeoJSON.
  */
 @interface MGLShapeCollection : MGLShape