Fenced codeblocks with extra spaces at the end don't work?

[sam (Sam Saffron)]

Rebaked OP and all seems fine

trailing spaces 
no 
longer 
break this

CommonMark testing started here!

Per our migration plans, I just enabled markdown.it at Meta. It is an excellent CommonMark compliant engine. I expect quite a few edges to be found during this period of testing. Do not open bugs about the new Engine, just reply here. I/we will be updating the top post here with the list of issues and striking out stuff as it is fixed. Current known issues (to be fixed) Onebox vanishes after you start typing and works not-super consistently pending…