add comma after case

docs/howto_guides/api_gui.md

@@ -155,7 +155,7 @@ If both the identifier and the collection name of the desired record is known, t
 4. Enter in the parameters in the **`GET /nmdcschema/{collection_name}`** endpoint. For this example, we will input `biosample_set` into the **collection_name** parameter and `{"part_of": "nmdc:sty-11-28tm5d36", "geo_loc_name.has_raw_value": {"$regex": "Colorado"}}` into the **filter** parameter. See the [Biosample Class](https://microbiomedata.github.io/nmdc-schema/Biosample/) in the NMDC Schema to view the applicable biosample attributes (slots); for this example, they are `part_of` and `geo_loc_name.has_raw_value`. Note that `$regex` conducts a full text search for the word "Colorado" in the `geo_loc_name.has_raw_value` attribute.
 5. Click **Execute**
 ![metadata example step4](../_static/images/howto_guides/api_gui/metadata_example_step4and5.png)
-6. View the results in JSON format, available to download by clicking **Download**; or copy the results by clicking the clipboard icon in the bottom right corner of the response. In this case two studies were retrieved. Note that the curl and request URL are provided as well.
+6. View the results in JSON format, available to download by clicking **Download**; or copy the results by clicking the clipboard icon in the bottom right corner of the response. In this case, two studies were retrieved. Note that the curl and request URL are provided as well.
 ![metadata example step6](../_static/images/howto_guides/api_gui/metadata_example_step6.png)