docs: Add solution to forward-ref in generic base

Issue-mkdocstrings#586: mkdocstrings/mkdocstrings#586

docs/guide/users/recommendations/python-code.md

@@ -412,3 +412,18 @@ Python's type system will let you use forward references in generic types when t
     ```
 
 While Griffe will load this code without error, the `'Bar'` forward reference won't be resolved to the actual `Bar` class. As a consequence, downstream tools like documentation renderers won't be able to output a link to the `Bar` class. We therefore recommend to avoid using forward references in base classes, if possible.
+
+Instead, you can try to declare or import the `Bar` class earlier, or make `FooBar` generic again but with a default type:
+
+```python
+class Foo[T]:
+    ...
+
+
+class FooBar[T=Bar](Foo[T]):
+    ...
+
+
+class Bar:
+    ...
+```