Workaround mkdocstrings bug

With griffe 0.35.0 (used by mkdocstrings), this line started to fail
with an error `Empty modules section at line ...`.

For now we are just working around it until the bug is fixed. See:
mkdocstrings/griffe#204

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/repo/config/nox/__init__.py

@@ -33,8 +33,8 @@
 nox.configure(config)
 ```
 
-If you need further customization or to define new sessions, you can use the following
-modules:
+If you need further customization or to define new sessions, you can use the
+following modules:
 
 - [`frequenz.repo.config.nox.config`][]: Low-level utilities to configure nox sessions.
   It defines the `Config` and CommandsOptions` classes and the actual implementation of