[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, 28 insertions, 7 deletions

diff --git a/platform/darwin/scripts/generate-style-code.js b/platform/darwin/scripts/generate-style-code.js
index 9e79d0a321..46f55c889c 100644
--- a/platform/darwin/scripts/generate-style-code.js
+++ b/platform/darwin/scripts/generate-style-code.js
@@ -46,6 +46,15 @@ _.forOwn(cocoaConventions, function (properties, kind) {
     })
 });
 
+String.prototype.wrap = function (cols, indent) {
+	let wrapRe = new RegExp(`(.{1,${cols - indent}})(?: +|\n|$)`, "gm");
+	return this.replace(wrapRe, "$1\n").replace(/\s+$/, "").indent(indent);
+};
+
+String.prototype.indent = function (cols) {
+	return this.replace(/^|\n/g, "$&" + " ".repeat(cols));
+};
+
 global.camelize = function (str) {
     return str.replace(/(?:^|-)(.)/g, function (_, x) {
         return x.toUpperCase();
@@ -126,7 +135,7 @@ global.testHelperMessage = function (property, layerType, isFunction) {
     }
 };
 
-global.propertyDoc = function (propertyName, property, layerType) {
+global.propertyDoc = function (propertyName, property, layerType, kind) {
     // Match references to other property names & values. 
     // Requires the format 'When `foo` is set to `bar`,'.
     let doc = property.doc.replace(/`([^`]+?)` is set to `([^`]+?)`/g, function (m, peerPropertyName, propertyValue, offset, str) {
@@ -157,11 +166,24 @@ global.propertyDoc = function (propertyName, property, layerType) {
         if (!property.units.match(/s$/)) {
             property.units += 's';
         }
-        doc += `
-
- This property is measured in ${property.units}.`;
+        doc += `\n\nThis property is measured in ${property.units}.`;
+    }
+    doc = doc.replace(/(p)ixel/gi, '$1oint').replace(/(\d)px\b/g, '$1pt');
+    if (kind !== 'enum') {
+        if ('default' in property) {
+            doc += `\n\nThe default value of this property is ${propertyDefault(property, layerType)}.`;
+            if (!property.required) {
+                doc += ' Set this property to `nil` to reset it to the default value.';
+            }
+        }
+        if ('requires' in property) {
+            doc += '\n\n' + propertyReqs(property, spec[`${kind}_${layerType}`], layerType);
+        }
+        if ('original' in property) {
+            doc += `\n\nThis attribute corresponds to the <a href="https://www.mapbox.com/mapbox-gl-style-spec/#layout-${layerType}-${property.original}"><code>${property.original}</code></a> layout property in the Mapbox Style Specification.`;
+        }
     }
-    return doc.replace(/(p)ixel/gi, '$1oint').replace(/(\d)px\b/g, '$1pt');
+    return doc;
 };
 
 global.propertyReqs = function (property, propertiesByName, type) {
@@ -365,11 +387,10 @@ const layers = Object.keys(spec.layer.type.values).map((type) => {
     }, []);
 
     return {
+        doc: spec.layer.type.values[type].doc,
         type: type,
         layoutProperties: _.sortBy(layoutProperties, ['name']),
         paintProperties: _.sortBy(paintProperties, ['name']),
-        layoutPropertiesByName: spec[`layout_${type}`],
-        paintPropertiesByName: spec[`paint_${type}`],
     };
 });