Updated SC2242 (markdown)

SC2242.md

@@ -21,7 +21,7 @@ String data should be written stdout, before an `exit 0` to exit with success.
 
 Errors should instead be written to stderr, with an `exit 1` (or higher) to exit with failure:
 
-```
+```sh
 if [ ! -f "$1" ]
 then
    echo "$1 is not a regular file" >&2