Fix broken link in partitioning.mdx (#317)

Author: Paul-Cornell

open-source/core-functionality/partitioning.mdx

@@ -298,7 +298,7 @@ elements = partition_html(url="https://python.org/", ssl_verify=False)
 
 ```
 
-For more information about the `partition_html` function, you can check the [source code here](https://github.com/Unstructured-IO/unstructured/blob/main/unstructured/partition/html.py).
+For more information about the `partition_html` function, you can check the [source code](https://github.com/Unstructured-IO/unstructured/blob/main/unstructured/partition/html/partition.py).
 
 ## `partition_image`