docs: add example of inference to gallery

docs/source/examples.rst

@@ -4,6 +4,7 @@ Example Gallery
 .. toctree::
 
    Emulator <../auto_examples/emulator/index>
+   Inference <../auto_examples/inference/index>
    Sampler <../auto_examples/sampler/index>
    Sensitivity <../auto_examples/sensitivity/index>
    Simulator <../auto_examples/simulator/index>