Fix docs cli example to give the promised run details table output (#…

…2298)

# Description
Existing docs give wrong command line at this url; user expects to get
tabular output, but command shown gives json output:
https://microsoft.github.io/promptflow/how-to-guides/manage-runs.html#show-run-metrics

ISSUE: #2299

The 

TEST PLAN:
updated md file renders in vscode, copy & paste of corrected command
line works when a real run name is used.


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Co-authored-by: BobbyO <bobbyo>

docs/how-to-guides/manage-runs.md

@@ -154,7 +154,7 @@ print(run)
 Get run details with TABLE format.
 
 ```bash
-pf run show --name <run-name>
+pf run show-details --name <run-name>
 ```
 
 ![img](../media/how-to-guides/run_show_details.png)