ref: more realistic params_show(stages) example

per #3459 (review)

content/docs/api-reference/params_show.md

@@ -64,15 +64,26 @@ The function parameters (below) let you restrict what's retrieved.
 
 ## Example: Filter by stage name(s)
 
-> Working on https://github.com/iterative/example-get-started
+> Working on https://github.com/iterative/example-get-started, file
+> `src/featurization.py`.
 
 `stages` can be a single name (string):
 
-```py
-import json
-import dvc.api
-params = dvc.api.get_params(stages="featurize")
-print(json.dumps(params, indent=2))
+```git
++import json
+-import yaml
+
+-params = yaml.safe_load(open("params.yaml"))["featurize"]
++import dvc.api
++
++params = dvc.api.get_params(stages="featurize")
++params = json.dumps(params, indent=2)
+
+ ...
+-max_features = params["max_features"]
+-ngrams = params["ngrams"]
++max_features = params["featurize"]["max_features"]
++ngrams = params["featurize"]["ngrams"]
 ```
 
 ```json