Add diff_version to API jobs list job versions

website/content/api-docs/jobs.mdx

@@ -632,7 +632,11 @@ The table below shows this endpoint's support for
 ### Parameters
 
 - `diffs` `(bool: false)` - Specifies if the Diffs field should be populated,
-  containing the structured diff between the current and last job version.
+  containing the structured diff between the current and last job version. This
+  is specified as a query string parameter.
+
+- `diff_version` `(int: <optional>)`: When `diffs=true`, this is the version
+  to compare the other versions to. This is specified as a query string parameter.
 
 - `:job_id` `(string: <required>)` - Specifies the ID of the job. This is
   specified as part of the path.