add more documentation

Author: dcharkes

pkgs/native_assets_builder/lib/src/build_runner/build_runner.dart

@@ -78,6 +78,9 @@ class NativeAssetsBuildRunner {
   /// The native assets build runner does not support reentrancy for identical
   /// [BuildInput] and [LinkInput]! For more info see:
   /// https://github.com/dart-lang/native/issues/1319
+  ///
+  /// The base protocol can be extended with [extensions]. See
+  /// [ProtocolExtension] for more documentation.
   Future<BuildResult?> build({
     required List<ProtocolExtension> extensions,
     required bool linkingEnabled,
@@ -177,6 +180,9 @@ class NativeAssetsBuildRunner {
   /// The native assets build runner does not support reentrancy for identical
   /// [BuildInput] and [LinkInput]! For more info see:
   /// https://github.com/dart-lang/native/issues/1319
+  ///
+  /// The base protocol can be extended with [extensions]. See
+  /// [ProtocolExtension] for more documentation.
   Future<LinkResult?> link({
     required List<ProtocolExtension> extensions,
     Uri? resourceIdentifiers,

pkgs/native_assets_cli/lib/src/code_assets/extension.dart

@@ -5,6 +5,8 @@
 import '../../code_assets_builder.dart';
 import 'validation.dart';
 
+/// The protocol extension for the `hook/build.dart` and `hook/link.dart`
+/// with [CodeAsset]s and [CodeConfig].
 final class CodeAssetExtension implements ProtocolExtension {
   final Architecture targetArchitecture;
   final OS targetOS;

pkgs/native_assets_cli/lib/src/data_assets/extension.dart

@@ -5,6 +5,8 @@
 import '../../data_assets_builder.dart';
 import 'validation.dart';
 
+/// The protocol extension for the `hook/build.dart` and `hook/link.dart`
+/// with [DataAsset]s.
 final class DataAssetsExtension implements ProtocolExtension {
   DataAssetsExtension();