Update synoptic_chart_generator.py

synoptic_chart_generator.py

@@ -98,7 +98,7 @@ def generate_synoptic_chart(json_input: str, output_format: str) -> str:
     }
 
     Returns:
-        str: The filepath to the generated PNG image file.
+        str: The filepath to the generated image file.
     """
     try:
         if not json_input.strip():