Fix code block rendering for cron syntax diagram

Change from plain code block to console with disabled line numbers and copy
functionality per docs engineer feedback. Improves visual presentation of the
cron schedule diagram.

Signed-off-by: Nic Cope <[email protected]>

Author: negz

content/master/operations/cronoperation.md

@@ -57,7 +57,7 @@ CronOperations are an alpha feature. You must enable Operations by adding
 
 CronOperations use standard cron syntax:
 
-```
+```console {linenos=false,copy-lines="none"}
 ┌───────────── minute (0 - 59)
 │ ┌───────────── hour (0 - 23)
 │ │ ┌───────────── day of the month (1 - 31)