Continued expressions commited to multiple lines

[fredrikekre]

I am not sure yet whether Runic will reformat to stay within a certain line width (gofmt does not) but if an expression have already commited to multiple lines, for example

some_function_name(argument1,
    argument2)

This should insert a newline after ( and before ):

some_function_name(
    argument1,
    argument2,
)

and, where applicable, add a trailing , to the last item.

[fredrikekre]

Also applies for arrays, tuples, function definitions and curly.