Implement PackageCategory.publicLibraries

Author: jcollins-g

lib/src/model.dart

@@ -4308,6 +4308,8 @@ class PackageCategory implements Comparable<PackageCategory> {
 
   List<Library> get libraries => _libraries;
 
+  Iterable<Library> get publicLibraries => libraries.where((l) => l.isPublic);
+
   @override
   String toString() => name;