chore: added a doc string for better args (#552)

This should improve the doc string for the arguments provided to
Kurtosis; I am not sure how to test this easily in the UI before merging
this but I ran the linter on this and the string is valid

<img width="894" alt="image"
src="https://github.com/kurtosis-tech/ethereum-package/assets/6670312/adea27d2-814b-4008-bb02-c72c40533094">

this is how it currently looks like; after this gets added the args will
have the string description given in this PR

<img width="894" alt="image"
src="https://github.com/kurtosis-tech/ethereum-package/assets/6670312/6fce937f-8203-4329-a978-3011f76ea15c">

this pure YAML/JSON field will still expect something like

```
args:
   participants:
```

main.star

@@ -52,6 +52,12 @@ PATH_TO_PARSED_BEACON_STATE = "/genesis/output/parsedBeaconState.json"
 
 
 def run(plan, args={}):
+    """Launches an arbitrarily complex ethereum testnet based on the arguments provided
+
+    Args:
+        arg: A YAML or JSON argument to configure the network; example https://github.com/kurtosis-tech/ethereum-package/blob/main/network_params.yaml
+    """
+
     args_with_right_defaults = input_parser.input_parser(plan, args)
 
     num_participants = len(args_with_right_defaults.participants)