Adjust workflow diagram in make_click_command()

- Use left-to-right order.
- Add debug code to only display the step(s) to the target key(s).

message_ix_models/workflow.py

@@ -361,7 +361,11 @@ def _func(context, go, truncate_step, target_step, **kwargs):
 
         if not go:
             path = context.get_local_path(f"{slug}-workflow.svg")
-            wf.visualize(str(path))
+            wf.visualize(
+                str(path),
+                # key=target_step,  # DEBUG Uncomment to show only a subset of steps
+                rankdir="LR",
+            )
             log.info(f"Workflow diagram written to {path}")
             return