Update docs/develop/python/observability.mdx

Author: fairlydurable

docs/develop/python/observability.mdx

@@ -219,7 +219,7 @@ These attributes are useful for querying Workflows based on the customer ID or t
 You can upsert Search Attributes to add or update Search Attributes from within Workflow code.
 
 To upsert custom Search Attributes, use the [`upsert_search_attributes()`](https://python.temporal.io/temporalio.workflow.html#upsert_search_attributes) method to pass a list of `SearchAttributeUpdate()`.
-These can be created via value_set calls on search attribute keys:
+These can be created via value_set calls on Search Attribute keys:
 
 ```python
 workflow.upsert_search_attributes([