code example formatting

doc/development/fe_guide/vuex.md

@@ -183,7 +183,7 @@ Remember that actions only describe that something happened, they don't describe
     },
     [types.REQUEST_ADD_USER_ERROR](state, error) {
       state.isAddingUser = true;
-      state.errorAddingUser = error∂;
+      state.errorAddingUser = error;
     },
   };
 ```