loop over custom tag result

[Igor-Palaguta]

In Leaf 3 we could loop not just over arrays from context, but we also could loop over custom tag result

Now in Leaf 4:

1. #for(language in #config("app", "languages")):
   Throws exception:
   LeafKit.LexerError.Reason.invalidParameterToken(\"#\")

2. #for(language in config("app", "languages")):
   Throws:
   "for loops expect single expression, 'name in names'"

[tonyarnold]

I'm seeing the same issue with the Nodes Flash package. I was expecting to be able to use the following in my templates (where flashes() is the custom tag):

#for(flash in flashes().all):

#endfor

[ptoffy]

@0xTim here you go, for the flashes library 🫡