spec: Add 'Default Arguments' heading, sentence, example
spec: Add 'Default Arguments' heading, sentence, example

The sentence and the accompanying example were stolen from SID-1.

shimib/scala,scala/scala,jvican/scala,martijnhoekstra/scala,felixmulder/scala,lrytz/scala,felixmulder/scala,shimib/scala,jvican/scala,slothspot/scala,martijnhoekstra/scala,lrytz/scala,shimib/scala,shimib/scala,jvican/scala,felixmulder/scala,scala/scala,martijnhoekstra/scala,martijnhoekstra/scala,jvican/scala,felixmulder/scala,slothspot/scala,scala/scala,slothspot/scala,slothspot/scala,scala/scala,martijnhoekstra/scala,shimib/scala,slothspot/scala,jvican/scala,felixmulder/scala,lrytz/scala,slothspot/scala,shimib/scala,lrytz/scala,scala/scala,scala/scala,jvican/scala,felixmulder/scala,jvican/scala,felixmulder/scala,slothspot/scala,martijnhoekstra/scala,lrytz/scala,lrytz/scala