Fix wrong doc string for dump_json (#438)

Author: alxbilger

bindings/Sofa/src/SofaPython3/Sofa/Core/Binding_ObjectFactory.cpp

@@ -225,7 +225,7 @@ void moduleAddObjectFactory(py::module &m) {
 
     factory.def_static("dump_json", [](){
         return sofa::core::ObjectFactoryJson::dump(ObjectFactory::getInstance());
-    }, doc::objectmodel::ObjectFactory_targets);
+    }, doc::objectmodel::ObjectFactory_dump_json);
 }
 
 } /// namespace sofapython3

bindings/Sofa/src/SofaPython3/Sofa/Core/Binding_ObjectFactory_doc.h

@@ -66,4 +66,9 @@ static auto ObjectFactory_getInstance =
     R"(
     Get the ObjectFactory singleton instance
     )";
-} /// namespace sofapython3::doc::forceField
+
+static auto ObjectFactory_dump_json =
+    R"(
+    Dump the ObjectFactory in a json string
+    )";
+} /// namespace sofapython3::doc::objectmodel