docs(eager-loading): add await to code example (#13414)

This line is missing an await, so the console.log does not actually log the expected Foo object as it hasn't been retrieved yet.

docs/manual/advanced-association-concepts/eager-loading.md

@@ -378,7 +378,7 @@ await sequelize.sync();
 const foo = await Foo.create({ name: 'foo' });
 const foo = await Foo.create({ name: 'foo' });
 const bar = await Bar.create({ name: 'bar' });
 const bar = await Bar.create({ name: 'bar' });
 await foo.addBar(bar);
 await foo.addBar(bar);
-const fetchedFoo = Foo.findOne({ include: Bar });
+const fetchedFoo = await Foo.findOne({ include: Bar });
 console.log(JSON.stringify(fetchedFoo, null, 2));
 console.log(JSON.stringify(fetchedFoo, null, 2));
 ```
 ```