Update sampler docs (#239)

* Update sampler docs

* Remove unused imports

* Metadata update

docs/models/index.rst

@@ -4,6 +4,7 @@ Models
 ========
 
 .. toctree::
+    :maxdepth: 1
 
     NeRF<nerf.md>
     Mip-NeRF<mipnerf.md>

docs/notebooks/index.rst

@@ -4,11 +4,11 @@ Components
 ==========
 
 .. toctree::
-    :maxdepth: 0
+    :maxdepth: 1
 
     visualize_cameras.ipynb
-    visualize_encoders.ipynb
     visualize_samplers.ipynb
-    visualize_spatial_distortions.ipynb
     visualize_samples.ipynb
+    visualize_spatial_distortions.ipynb
+    visualize_encoders.ipynb