Fix GDNative C example

(cherry picked from commit 3635d341e29df402f0d315f4ca6e0cdb1fe59f43)

tutorials/plugins/gdnative/gdnative-c-example.rst

@@ -228,7 +228,7 @@ library and communicates back to the engine what objects we make available.
         godot_instance_destroy_func destroy = { NULL, NULL, NULL };
         destroy.destroy_func = &simple_destructor;
 
-        nativescript_api->godot_nativescript_register_class(p_handle, "Simple", "Reference",
+        nativescript_api->godot_nativescript_register_class(p_handle, "SIMPLE", "Reference",
                 create, destroy);
 
         godot_instance_method get_data = { NULL, NULL, NULL };
@@ -236,7 +236,7 @@ library and communicates back to the engine what objects we make available.
 
         godot_method_attributes attributes = { GODOT_METHOD_RPC_MODE_DISABLED };
 
-        nativescript_api->godot_nativescript_register_method(p_handle, "Simple", "get_data",
+        nativescript_api->godot_nativescript_register_method(p_handle, "SIMPLE", "get_data",
                 attributes, get_data);
     }
 
@@ -495,7 +495,7 @@ Creating the NativeScript (``.gdns``) file
 ------------------------------------------
 
 With our ``.gdnlib`` file we've told Godot how to load our library, now we need
-to tell it about our "Simple" object class. We do this by creating a
+to tell it about our "SIMPLE" object class. We do this by creating a
 :ref:`NativeScript <class_NativeScript>` resource file with ``.gdns`` extension.
 
 Like done for the GDNativeLibrary resource, click the button to create a new
@@ -504,7 +504,7 @@ resource in the Inspector and select ``NativeScript``:
 .. image:: img/nativescript_resource.png
 
 The inspector will show a few properties that we need to fill. As *Class Name*
-we enter "Simple" which is the object class name that we declared in our C
+we enter "SIMPLE" which is the object class name that we declared in our C
 source when calling ``godot_nativescript_register_class``. We also need to
 select our ``.gdnlib`` file by clicking on *Library* and selecting *Load*: