Added comment for example (#759)

Signed-off-by: Mandana Vaziri <[email protected]>

Author: vazirim

examples/tools/calc.pdl

@@ -21,7 +21,7 @@ text:
   parser: json
   spec: [{ name: str, arguments: { expr: str }}]  
   parameters:
-    drop_params: true
+    drop_params: true  # This is needed because the model does not support structured decoding. It directs LiteLLM to ignore parameters sent for structured decoding.
 - "\n"
 - if: ${ actions[0].name == "calc" }
   then: