Update `cron` docs to call out special `fugit` syntax

What does this MR do and why?

I was writing a cron job. I saw this example, however the docs say the examples are from the man page or from wikipedia

This confused me, as both suggest that % is invalid and creates a newline

Took a few minutes for me to realize it is part of the fugit parser extensions.

I'd like to make that more clear by calling it out in-line somewhere closer to the example

Screenshots or screen recordings

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