internal/impl: rename legacyProtoMethods as aberrantProtoMethods

This variable is only used by the aberrantMessage type,
rename it to properly reflect what it is used for.

Change-Id: I081e8954eb1b282f01f6d2d764bffaf31c6677e9
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/245077
Reviewed-by: Damien Neil <dneil@google.com>
diff --git a/internal/impl/legacy_message.go b/internal/impl/legacy_message.go
index d5347cc..b1d66c5 100644
--- a/internal/impl/legacy_message.go
+++ b/internal/impl/legacy_message.go
@@ -380,7 +380,7 @@
 	Merge(protoiface.MessageV1)
 }
 
-var legacyProtoMethods = &piface.Methods{
+var aberrantProtoMethods = &piface.Methods{
 	Marshal:   legacyMarshal,
 	Unmarshal: legacyUnmarshal,
 	Merge:     legacyMerge,
@@ -505,7 +505,7 @@
 	return true
 }
 func (m aberrantMessage) ProtoMethods() *piface.Methods {
-	return legacyProtoMethods
+	return aberrantProtoMethods
 }
 func (m aberrantMessage) protoUnwrap() interface{} {
 	return m.v.Interface()