reproducibility: hide non-reproducible settings from manual

Because the manual is generated from default values which are themselves
generated from various sources (cpuid, bios settings (kvm), number of
cores). This commit hides non-reproducible settings from the manual
output.

src/libutil/abstract-setting-to-json.hh

@@ -10,6 +10,7 @@ std::map<std::string, nlohmann::json> BaseSetting<T>::toJSONObject()
     auto obj = AbstractSetting::toJSONObject();
     obj.emplace("value", value);
     obj.emplace("defaultValue", defaultValue);
+    obj.emplace("documentDefault", documentDefault);
     return obj;
 }
 }