examples: lang: Test that each of the mcl examples compiles

We let these rot, so fixup the issues and test them!

examples/lang/class-include.mcl

@@ -10,7 +10,7 @@ class foo {
 $wow = "this is wow"	# gets captured
 
 class bar($a, $b) { # a parameterized class
-	print "bar-"+ $a {
+	print ["bar-"+ $a,] {
 		msg => fmt.printf("inside bar: %s", $b + "; " + $wow),
 
 		Meta:autogroup => false,