Fix error in DartDoc, add missing Since annotation.

Apaprently the landing of the previous DartDoc introduced an error
in the DartDoc process.
Removing the entire comment doesn't change that, so I'm not sure
where the actual error is.
Anyway, this fixes the links that weren't working,
and it adds a missing `Since` annotation at the same time.

Change-Id: I92ac23a32ccc9ddbaf9a708b21fe3521c4103513
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/241011
Commit-Queue: Lasse Nielsen <lrn@google.com>
Auto-Submit: Lasse Nielsen <lrn@google.com>
Reviewed-by: Nate Bosch <nbosch@google.com>
Commit-Queue: Nate Bosch <nbosch@google.com>

sdk/lib/core/errors.dart

@@ -96,8 +96,8 @@ class Error {
 
   /// Throws [error] with associated stack trace [stackTrace].
   ///
-  /// Behaves like <code>throw [error]</code> would
-  /// if the [current stack trace](StackTrace.current) was [stackTrace]
+  /// Behaves like `throw error` would
+  /// if the [current stack trace][StackTrace.current] was [stackTrace]
   /// at the time of the `throw`.
   ///
   /// Like for a `throw`, if [error] extends [Error], and it has not been

sdk/lib/typed_data/typed_data.dart

@@ -15,6 +15,7 @@ library dart.typed_data;
 
 import "dart:_internal" show Since, UnmodifiableListBase;
 
+@Since("2.10")
 export "dart:_internal" show BytesBuilder;
 
 part "unmodifiable_typed_data.dart";