[frontend] Add missing newline to parrot_debugger flags error message
[frontend] Add missing newline to parrot_debugger flags error message

parrot_debugger doesn't take -x or --xxxx flags.  The error message didn't
have a newline, and thus the prompt doesn't return properly.  This commit
fixes this issue.

tkob/parrot,youprofit/parrot,parrot/parrot,FROGGS/parrot,FROGGS/parrot,tkob/parrot,parrot/parrot,youprofit/parrot,parrot/parrot,youprofit/parrot,tkob/parrot,FROGGS/parrot,youprofit/parrot,parrot/parrot,FROGGS/parrot,FROGGS/parrot,tkob/parrot,youprofit/parrot,tkob/parrot,youprofit/parrot,tkob/parrot,youprofit/parrot,FROGGS/parrot,FROGGS/parrot,parrot/parrot,youprofit/parrot,FROGGS/parrot,tkob/parrot,tkob/parrot