add __init__.py and fix references

Author: OwenMcDonnell

sdk/python/examples/controls/slider/__init__.py

@@ -4,7 +4,6 @@ examples: ../../examples/controls/slider
 example_images: ../test-images/examples/material/golden/macos/slider
 ---
 
-<!-- {{ class_summary(class_name) }} -->
 {{ class_summary(class_name, example_images + "/image_for_docs.png", image_caption="Default and disabled sliders") }}
 
 ## Examples
@@ -17,7 +16,7 @@ example_images: ../test-images/examples/material/golden/macos/slider
 --8<-- "{{ examples }}/basic.py"
 ```
 
-{{ image(example_images + "/basic.gif", alt="basic", width="80%") }}
+{{ image(example_images + "/basic.png", alt="basic", width="80%") }}
 
 
 ### Setting a custom label
@@ -26,7 +25,7 @@ example_images: ../test-images/examples/material/golden/macos/slider
 --8<-- "{{ examples }}/custom_label"
 ```
 
-{{ image(example_images + "/custom_label.gif", alt="custom-label", width="80%") }}
+{{ image(example_images + "/custom_label.png", alt="custom-label", width="80%") }}
 
 
 ### Handling events
@@ -35,13 +34,8 @@ example_images: ../test-images/examples/material/golden/macos/slider
 --8<-- "{{ examples }}/handling_events.py"
 ```
 
-{{ image(example_images + "/handling_events.gif", alt="handling-events", width="80%") }}
+{{ image(example_images + "/handling_events.png", alt="handling-events", width="80%") }}
 
 
-### Random values
-
-```python
---8<-- "{{ examples }}/random_values.py"
-```
 
 {{ class_members(class_name) }}