[core libs] address ~5 analysis issues in the docs for dart:isolate

Change-Id: Iebe275335fd098419ede97dbb8baff8efaf9dc1e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/241161
Reviewed-by: Jonas Termansen <sortie@google.com>
Reviewed-by: Lasse Nielsen <lrn@google.com>
Reviewed-by: William Hesse <whesse@google.com>
Commit-Queue: Devon Carew <devoncarew@google.com>

sdk/lib/isolate/isolate.dart

@@ -24,6 +24,12 @@ import "dart:typed_data" show ByteBuffer, TypedData, Uint8List;
 
 part "capability.dart";
 
+// Examples can assume:
+// Isolate findSomeIsolate() => Isolate.current;
+// void untrustedCode(Isolate isolate) {}
+// RawReceivePort rawPort = RawReceivePort();
+// void actualHandler() {}
+
 /// Thrown when an isolate cannot be created.
 class IsolateSpawnException implements Exception {
   /// Error message reported by the spawn operation.
@@ -734,8 +740,8 @@ abstract class RawReceivePort {
   ///
   /// The handler is invoked in the [Zone.root] zone.
   /// If the handler should be invoked in the current zone, do:
-  /// ```dart
-  /// rawPort.handler = Zone.current.bind(actualHandler);
+  /// ```dart import:async
+  /// rawPort.handler = Zone.current.bindCallback(actualHandler);
   /// ```
   ///
   /// The handler must be a function which can accept one argument

tools/bots/test_matrix.json

@@ -3688,6 +3688,7 @@
             "dart:convert",
             "dart:developer",
             "dart:ffi",
+            "dart:isolate",
             "dart:js",
             "dart:js_util",
             "dart:math",