Fix a usage example in the Go indexer package comment.
Summary: No functional change.
Reviewers: #core_team, zarko
Subscribers: #core_team
// var unit *apb.CompilationUnit = ...
//
// // Parse the sources and resolve types.
-// pi, err := indexer.Resolve(unit, pack, indexer.AllTypeInfo())
+// pi, err := indexer.Resolve(unit, pack, &indexer.ResolveOptions{
+// Info: indexer.AllTypeInfo(),
+// })
// if err != nil {
// log.Fatal("Resolving failed: %v", err)
// }
