add missing deprecation of FunctionCallback::Callee

It was removed ages ago, but never marked as deprecated.

Author: kkoopa

nan_callbacks_12_inl.h

@@ -106,7 +106,9 @@ class FunctionCallbackInfo {
   }
 
 #if NODE_MAJOR_VERSION < 10
-  inline v8::Local<v8::Function> Callee() const { return info_.Callee(); }
+  NAN_DEPRECATED inline v8::Local<v8::Function> Callee() const {
+    return info_.Callee();
+  }
 #endif
   inline v8::Local<v8::Value> Data() const { return data_; }
   inline v8::Local<v8::Object> Holder() const { return info_.Holder(); }

nan_callbacks_pre_12_inl.h

@@ -136,7 +136,9 @@ class FunctionCallbackInfo {
     return ReturnValue<T>(return_value_);
   }
 
-  inline v8::Local<v8::Function> Callee() const { return args_.Callee(); }
+  NAN_DEPRECATED inline v8::Local<v8::Function> Callee() const {
+    return args_.Callee();
+  }
   inline v8::Local<v8::Value> Data() const { return data_; }
   inline v8::Local<v8::Object> Holder() const { return args_.Holder(); }
   inline bool IsConstructCall() const { return args_.IsConstructCall(); }