Newline after opening parenthesis for tag declaration fails to be parsed

[dahlia]

Given the following IDL code:

union transport
    = phone_transport (
        text from,
        text to)
    | yellowid_transport (
        text key,
        text to)
    | chanined_transport (
        [transport] transports)
    ;

It currently fails to be parsed:

message_schema/entity.nrm:16:24:
unexpected newline
expecting union tag fields

    = phone_transport (
                       ^

Reported by @yjroot.

[dahlia]

@yjroot Fixed it.