[sdk] Clarify SendPort.send comment

The comment referred to "dart vm" which confused users reading
documentation. Use "Dart Native" instead and link to the page on the
site describing it.

[email protected], [email protected]

Issue #38964

Change-Id: I50cf1b67d9e709d81a1ca7dced8da2f84488873e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/161781
Reviewed-by: Lasse R.H. Nielsen <[email protected]>
Commit-Queue: Vyacheslav Egorov <[email protected]>

Author: mraleph

sdk/lib/isolate/isolate.dart

@@ -624,7 +624,9 @@ abstract class SendPort implements Capability {
    * In the special circumstances when two isolates share the same code and are
    * running in the same process (e.g. isolates created via [Isolate.spawn]), it
    * is also possible to send object instances (which would be copied in the
-   * process). This is currently only supported by the dart vm.
+   * process). This is currently only supported by the
+   * [Dart Native](https://dart.dev/platforms#dart-native-vm-jit-and-aot)
+   * platform.
    *
    * The send happens immediately and doesn't block.  The corresponding receive
    * port can receive the message as soon as its isolate's event loop is ready