analyzer: Remove TODO that is DONE

Change-Id: I15a85d31b797d99d68c94b3c0fe433c18d9effbe
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/432905
Commit-Queue: Paul Berry <[email protected]>
Auto-Submit: Samuel Rawlins <[email protected]>
Reviewed-by: Paul Berry <[email protected]>

Author: srawlins

pkg/analyzer/lib/src/generated/resolver.dart

@@ -330,9 +330,6 @@ class ResolverVisitor extends ThrowingAstVisitor<void>
   /// used to access the types from the core library. The [errorListener] is the
   /// error listener that will be informed of any errors that are found during
   /// resolution.
-  ///
-  // TODO(paulberry): make [featureSet] a required parameter (this will be a
-  // breaking change).
   ResolverVisitor(
     InheritanceManager3 inheritanceManager,
     LibraryElementImpl definingLibrary,