Unidoc needed this� change

Semantically this should be identical

Author: eed3si9n

src/main/java/xsbti/compile/DefaultExternalHooks.java

@@ -21,7 +21,7 @@ public DefaultExternalHooks(Optional<ExternalHooks.Lookup> lookup, Optional<Clas
     }
 
     @Override
-    public Optional<Lookup> getExternalLookup() {
+    public Optional<ExternalHooks.Lookup> getExternalLookup() {
         return lookup;
     }
 
@@ -42,7 +42,7 @@ public ExternalHooks withExternalClassFileManager(ClassFileManager externalClass
     }
 
     @Override
-    public ExternalHooks withExternalLookup(Lookup externalLookup) {
+    public ExternalHooks withExternalLookup(ExternalHooks.Lookup externalLookup) {
         return new DefaultExternalHooks(Optional.of(externalLookup), this.getExternalClassFileManager());
     }
 }