Run gofmt on corpus and include deprecation.

registry.go

@@ -50,7 +50,6 @@ type container struct {
 	name       string
 }
 
-
 type registry struct {
 	mutex               sync.RWMutex
 	signatureContainers map[string]container
@@ -66,6 +65,9 @@ type Registry interface {
 	// Create a http.HandlerFunc that is tied to a Registry such that requests
 	// against it generate a representation of the housed metrics.
 	Handler() http.HandlerFunc
+	// This is a legacy version of Handler and is deprecated.  Please stop
+	// using.
+	YieldExporter() http.HandlerFunc
 }
 
 // This builds a new metric registry.  It is not needed in the majority of