[docs] move several older dart: web libraries into a 'legacy' category

Change-Id: Ie4c3413191c14976f85614fab11ee94830a25aab
CoreLibraryReviewExempt: documentation only change in the web libraries
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/345566
Auto-Submit: Devon Carew <devoncarew@google.com>
Commit-Queue: Devon Carew <devoncarew@google.com>
Reviewed-by: Kevin Moore <kevmoo@google.com>

sdk/lib/html/dart2js/html_dart2js.dart

@@ -9,7 +9,7 @@
 ///
 /// For information on writing web apps with Dart, see https://dart.dev/web.
 ///
-/// {@category Web}
+/// {@category Web (Legacy)}
 /// {@canonicalFor dart:_internal.HttpStatus}
 library dart.dom.html;
 

sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart

@@ -61,7 +61,7 @@
 /// MDN provides [API
 /// documentation](https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API).
 ///
-/// {@category Web}
+/// {@category Web (Legacy)}
 library dart.dom.indexed_db;
 
 import 'dart:async';

sdk/lib/js/js.dart

@@ -81,7 +81,7 @@
 ///
 ///     var jsArray = JsObject.jsify([1, 2, 3]);
 ///
-/// {@category Web}
+/// {@category Web (Legacy)}
 library dart.js;
 
 import 'dart:collection' show ListMixin;

sdk/lib/js_util/js_util.dart

@@ -8,7 +8,7 @@
 /// You should only use these methods when the same effect cannot be achieved
 /// with `@JS()` annotations.
 ///
-/// {@category Web}
+/// {@category Web (Legacy)}
 library dart.js_util;
 
 // Examples can assume:

sdk/lib/svg/dart2js/svg_dart2js.dart

@@ -5,7 +5,7 @@
 /// refer to the
 /// [Scalable Vector Graphics Specification](http://www.w3.org/TR/SVG/).
 ///
-/// {@category Web}
+/// {@category Web (Legacy)}
 library dart.dom.svg;
 
 import 'dart:async';

sdk/lib/web_audio/dart2js/web_audio_dart2js.dart

@@ -1,6 +1,6 @@
 /// High-fidelity audio programming in the browser.
 ///
-/// {@category Web}
+/// {@category Web (Legacy)}
 library dart.dom.web_audio;
 
 import 'dart:async';

sdk/lib/web_gl/dart2js/web_gl_dart2js.dart

@@ -1,6 +1,6 @@
 /// 3D programming in the browser.
 ///
-/// {@category Web}
+/// {@category Web (Legacy)}
 library dart.dom.web_gl;
 
 import 'dart:async';

tools/write_dartdoc_options_file.py

@@ -32,7 +32,7 @@ def Main(argv):
     if revision is None:
         revision = 'main'
     output = '''dartdoc:
-  categoryOrder: ["Core", "VM", "Web"]
+  categoryOrder: ["Core", "VM", "Web", "Web (Legacy)"]
   linkToSource:
     root: '.'
     uriTemplate: 'https://github.com/dart-lang/sdk/blob/%s/sdk/%%f%%#L%%l%%'