Add 'C' formatting code

Author: tbrowder

doc/Language/pod.pod6

@@ -86,7 +86,7 @@ by a whitespace character. N<This feature is not yet completely implemented.
 All configuration information currently must be provided on the same
 line as the C<=begin> marker line or C<=for name> for paragraph blocks.>
 
-Some of these options have a predetermined value; specifically, <:numbered>
+Some of these options have a predetermined value; specifically, C<:numbered>
 is used to specify that the block item or lines will be numbered.
 
 =for code