[Pharo-project] small fix to help newbies

Hi folks, I'm sending this email to both Squeak-dev and Pharo-project as you can see. This is to suggest a fix. I typed this on a workspace: closure := [:x | Transcript show: x]. closure value: "hey". And when I "did it", the VM had me looking at this: closure := [:x | Transcript show: x]. closure value: "hey". Argument expected -> Which is cryptic at best for a newbie. I visited #squeak@irc.freenode.net and asked there. Ken Causey helped me out and even he missed the difference between "" and '' for a second. I believe it would be beneficial to newbies to have this enhanced somehow, to point out the fact that strings aren't double-quoted. Thanks, Peter